Marks:
All Magic Penetration for increased damage.
Armor Marks can be taken instead for increased defense but because of other sources of increased defense, the magic penetration creates a balance by adding offense.


Seals:
Armor Seals may be the best quality and adds some helpful defensive stats.


Glyphs and Quints:
CDR items for Katarina are not great and she should not be prioritized for blue buff so getting a lot of CDR from runes is helpful. The scaling ones help her get a quite significant amount over time.

Ignite:
This is sometimes excess damage but it can be very effective nevertheless and is especially helpful against escaping enemies.
It also applies a Grievous Wounds effect which makes it a helpful option against enemies with significant healing potential.
Consider these effects and its 210-second cooldown when comparing it to other Summoner Spells and choose what you prefer.

Exhaust:
This can be used defensively or offensively.
It is especially helpful against high-damage enemies, fast-moving enemies and enemies with high attack speed.
The Armor and Magic Resistance reduction is mainly helpful earlier in the game.
Consider these effects and its 210-second cooldown when comparing it to other Summoner Spells and choose what you prefer.

Cleanse:
It is helpful against long duration disables but it may be insignificant to have its effects once every few minutes if the enemy team has a lot of disables.

Barrier v.s. Heal:
Barrier has a higher point bonus on the casting champion at every level than Heal.
The point bonus of Heal can also be reduced by half due to a Grievous Wounds effect.
Heal, however, gives a bonus to a nearby allied champion as well.
Barrier can absorb/negate a slightly higher amount of burst damage than Heal on the casting champion.
Bonuses from Heal remain unlike that of Barrier since it is a short-duration shield.
Barrier can be mistimed and wasted but Heal always gives a bonus as long as there is missing Health from the casting champion and/or a nearby allied champion.
Barrier has a 30-second lower cooldown than Heal.
^ Consider all these details and choose what you prefer... or both. :D


Clairvoyance:
I recommend this whether the champion is a support or not. It may be generally better than other Summoner Spells if used frequently and appropriately. It depends on whether you're playing the 'defense game', 'offense game' or 'utility game'. Clairvoyance is a utility and helps with a nice vision effect. It can reveal hiding champions, buff steal attempts, dangerous brushes, impending ganks and more. It may be significant to have this effect every 60 seconds.
Consider your playstyle and choose this if it suits.

Teleport:
This can be helpful to get to lanes or jungles fast (depending on what you're teleporting to). It can be used to jump in team fights fast from afar or for attempting to escape when ground/river/air movement isn't helping enough.
Remember that its channel can be interrupted by disables.
Consider these effects and its 240/300-second cooldown when comparing it to other Summoner Spells and choose what you prefer.

Flash v.s. Ghost:
Flash enables quicker dodges and engages, and may allow dodges in ways that Ghost cannot accomplish (such as against projectiles and across walls and cliffs).
Ghost is helpful in chasing champions to do repeated damage over time.
Ghost also has a 90-second lower cooldown than Flash.
^ Consider all these details and choose what you prefer... or both. :D

Of all these spells, however, I definitely do not recommend Ghost on Katarina.

General starting combo (best for most situations):
1 Cloth Armor
5 Health Potions

Cloth Armor will reduce damage from physical basic attacks which is common across all champions. This will reduce the poke potential of the enemy.
Katarina will also have the maximum of 5 Health Potions for health sustain during laning phase so that she can stay out longer and potentially farm more.

Other options:
Doran's Shield and a Health Potion
- This can be as good or better than the first combo as long as you don't get harassed regularly.
The Cloth Armor and Health Potions will be a safe choice for a lot of situations especially if there are threatening poke champions on the enemy team that Kat might face.
In knowing that all or most of the enemy champions will not be threatening in such a way, however, the Doran's Shield and Health Potion can be taken, especially if the enemy is ranged and has single target spells.

Boots of Speed and 4 Health Potions
- Boots of Speed to move fast into enemy jungle and place ward? Probably not worth it 'cause what you gonna do with the boots after? Return to lane fast?! Be bold but patient and still place wards. :)
- Boots of Speed to invade fast? How is it going to help you in a fight? There are other starting items that will be more helpful.
- If you're just going to head out to lane and wait for minion spawn, then you certainly don't need Boots of Speed 'cause everybody gets to lane on time. Hooray! :D
- Furthermore, if you're considering having Boots of Speed for quick early game roaming ganks, that's only for a little improvement in trying to reach another lane on time and a chance to gank, the outcome of which you may not be certain. Boots of speed just for that little chance is not worth it. It's better to get another item that will help you out more in your lane.
+25 movement speed in lane may be quite insignificant unless you dodgin' ants.

Amplifying Tome and Health Potion
- I do not recommend this for most situations but it can be taken if you are sure that you are a bigger threat than any enemy you will face. This is for more aggressive play early on.

Doran's Ring and 2 Health Potions
- Individually, this combo is better than the Amplifying Tome combo. The Amplifying Tome combo may only be considered better in the sense that it can be used to build another item that Kat will use.
Analysis:
First of all, ignore the mana features of Doran's Ring because Kat doesn't use mana.
Comparing Amplifying Tome and Doran's Ring alone, you will see that Doran's Ring has 5AP less but has 60HP which the Tome does not have. Now add the extra Health Potion you get with the Doran's Ring combo. It turns out better by itself as a combo, i.e. without considering upgrades.

Health Potions should be prioritized. It may be best to get up to 5 of them before purchasing anything else, but less of them can be bought along with other non-consumables. Just ensure that you have sufficient health sustain. Even if you are dominating or very safe-playing, you may face unexpected damage. Health Potions can sustain your health for survivability and suitability for various situations out on the map, and prevent the need from having to return to base too early.
If you are depending a lot on health sustain, you can get a Crystalline Flask in addition to Health Potions. Do not, however, purchase a Crystalline Flask unless you already have at least 3 Health Potions in your inventory. A full Crystalline Flask can heal up to 360HP. With a small amount of gold, purchasing 5 Health Potions is better than purchasing a Crystalline Flask and 2 Health Potions or less;
5 Health Potions = 750HP regeneration
Crystalline Flask + 2 Health Potions = 660HP regeneration < 750HP
Crystalline Flask + 3 Health Potions = 810HP regeneration > 750HP

^ This is considering the total amount of heal you get on going back out to the rest of the map.
Of course the Flask will refill when returning to shop but this is under the consideration of the long-term effect.
On returning to base, your gold may work out such that you can only get Health Potions and a component item or even a complete item. If so just ignore the flask. It can be purchased on your next return to base or not at all, but I recommend it; it is a helpful boost to overall regeneration potential, especially for a champion without significant built-in healing. It, however, should be bought early enough in the match to use as many charges of it as you can throughout the match.
Although Kat can't use the mana regeneration feature of the flask since she doesn't use mana, it is still helpful for the HP regen.
Crystalline Flask costs 345 gold.
345 gold = approximately 10 Health Potions (350 gold)
10 Health Potions = 1500HP regeneration
1500HP / 120HP = 12.5
It therefore takes 13 activations of Crystalline Flask for it to just surpass cost-effectiveness (for Katarina), using Health Potions as the reference.
This means 4 returns to base after purchasing the Flask.
I think this is a good deal overall and it's just a 345-gold item.


If Katarina is facing a significant physical damage lane threat, Seeker's Armguard can be bought early.
If not, Luden's Echo should be focused on first.
In between building Luden's Echo, a Negatron Cloak or Null Magic Mantle can be bought for survivability against magic damage if needed but AP is priority.
Boots can also be bought in between building Seeker's Armguard or Luden's Echo but again AP is priority.
Wards can be purchased with extra gold.

Sorcerer's Shoes:
25ms = 325g
45ms = 585g
Sorcerer's Shoes cost = 1100g
15 magic pen = 1100g - 585g = 515g
Using Needlessly Large Rod as the calculation reference:
60AP = 1250g
515g = 24.72AP
Is getting the 15 magic pen from Sorcerer's Shoes greater than 515g in AP?

Considering an enemy with 30MR:
30MR = approximately 23% magic damage reduction
30MR - 15MR = 15MR = approximately 13% magic damage reduction
Difference = approximately 10%
This means that with 15 magic pen, magic damage dealt will be 10% more.

In the following examples, other sources of bonus AP, bonus AD, bonus magic pen/reduction, and bonus MR are not considered, for simplicity.
Let's look at Bouncing Blades:
lvl 1 total damage = 75
Bonus damage with 15 magic pen = 10% of 75 = 7.5
Bonus damage with +24.72AP = 60% of 24.72 = 14.8

lvl 2 total damage = 115
Bonus damage with 15 magic pen = 10% of 115 = 11.5

lvl 3 total damage = 155
Bonus damage with 15 magic pen = 10% of 155 = 15.5 > 14.8

15 magic pen is, therefore, more efficient than 24.72AP at lvl 3 for the Q.


Let's look at Sinister Steel:
lvl 1 damage = 40
Bonus damage with 15 magic pen = 10% of 40 = 4
Bonus damage with +24.72 AP = 25% of 24.72 = 6.2

lvl 2 damage = 80
Bonus damage with 15 magic pen = 10% of 80 = 8 > 6.2

15 magic pen is, therefore, more efficient than 24.72AP at lvl 2 for the W.


Let's look at Shunpo:
lvl 1 damage = 40
Bonus damage with 15 magic pen = 10% of 40 = 4
Bonus damage with +24.72 AP = 25% of 24.72 = 6.2

lvl 2 damage = 70
Bonus damage with 15 magic pen = 10% of 70 = 7 > 6.2

15 magic pen is, therefore, more efficient than 24.72AP at lvl 2 for the E.


Let's look at Death Lotus:
lvl 1 damage = 350
Bonus damage with 15 magic pen = 10% of 350 = 35
Bonus damage with +24.72 AP = 250% of 24.72 = 61.8

lvl 2 damage = 550
Bonus damage with 15 magic pen = 10% of 550 = 55

lvl 3 damage = 750
Bonus damage with 15 magic pen = 10% of 750 = 75 > 61.8

15 magic pen is, therefore, more efficient than 24.72AP at lvl 3 for the Ult.


Conclusion: AP will benefit Katarina more than Sorcerer's Shoes at her lower levels.
Remember that the % damage increase from flat magic pen decreases as the enemy stacks MR.
Although these calculations are based on just a 515 gold consideration it makes it clear that for bonus magic damage for Katarina, AP is better earlier on instead of rushing Sorcerer's Shoes and this allows for a selection of another type of boots that can be helpful in a different way.

Boots of Mobility:
Cost: 800g
Base MS: 25
25 MS = 325g
Max MS = 105 = 1365g

Boots of Mobility therefore has significant cost efficiency when considering its out-of-combat bonus.
It is a worthwhile buy as long as the champion needs such an amount of ms and/or based on the playstyle of the Summoner.


Ionian Boots of Lucidity:
Cost: 1000g
MS: 45 = 585g
15% cooldown reduction = 1000g - 585g = 415g

If the costs of the ms and cdr above are satisfying, based on the champion and other comparisons, it can be a worthwhile buy.


Boots of Swiftness:
Cost: 1000g
MS: 60 = 780g
Slow Resist effect = 1000g - 780g = 220g

Boots of Swiftness is effective against champions or a team of champions with numerous slowing abilities. After considering this, it should be bought based on the worthiness of the cost for the ms and special effect.
This item is especially effective against large slow percentages.
Tenacity (such as with Mercury's Treads) is effective against long slow durations.
Boots of Speed may be a preferable choice over Mercury's Treads for champions that have speed bonuses sufficient to make the +15ms worthwhile.
Otherwise, it may be more beneficial to have +25MR as long as it will be needed.


Mercury's Treads:
Cost: 1200
MS: 45 = 585g
+25 Magic Resistance from Null Magic Mantle = 450g
Tenacity = 1200g - 585g + 450g = 165g

Mercury's Treads is effective against champions or a team of champions with numerous crowd control abilities, the durations of which Tenacity reduces.
After considering this, it should be bought based on the worthiness of the cost for the MS, MR and Tenacity.


Ninja Tabi:
Cost: 1000g
MS = 45 = 585g
Using Cloth Armor as reference: 15 armor = 300g
25 armor = 500g
Total = 1085g
The item is cost efficient without even considering the bonus effect.

Ninja Tabi is effective against champions or a team of champions with high damage from basic attacks. As long as the ms and armor is desired and seen as cost-worthy, this item is a cost-efficient purchase.


DO NOT BUY BERSERKER'S GREAVES FOR KATARINA!

Alacrity:
20MS = 260g
Enchantment Cost: 475g

This is too expensive unless there is nothing better/remaining to spend 475g on.


Furor:
With Boots of Mobility (Boots with lowest in-combat ms) on Katarina, she'll have 370MS which will increase in combat (with single-target spells or attacks) to 414 with the Furor bonus. This is a 44MS bonus which makes it better than Alacrity for in-combat purposes.
Alacrity is more suitable for out-of-combat movement.

Furor Enchantment Cost: 650g
44MS = 572g

With a +45MS boots, Katarina will have 390MS which will increase in combat (with single-target spells or attacks) to 437 with the Furor bonus. This is a 47MS bonus.
47MS = 611g

With a +60MS boots, Katarina will have 405MS which will increase in combat (with single-target spells or attacks) to 454 with the Furor bonus. This is a 49MS bonus.
49MS = 637g

The Furor Enchantment can be purchased if it is seen as necessary to have such a boost in combat and if 650g cannot be spent on anything better at the time.
Katarina, however, generally does not need this as she already gains a significant boost in movement speed from Sinister Steel.


Captain:
This is more suitable for a support champion to purchase but it can be purchased for Katarina if it may be situationally more beneficial than the other Enchantments.


Distortion:
This can be purchased if Katarina has Teleport, Flash, Ghost or any combination of these Summoner Spells, and if none of the other Enchantments are seen as more helpful.
475g is a good deal for all the bonuses of Distortion.
This Enchantment should not be purchased if the Teleport, Ghost and Flash are on cooldown with a long time remaining (this is considering you'll return to base before the end of the cooldown). It may be better to spend the gold on something more readily available.


Homeguard:
This is more suitable for emergency situations such as when your base is being invaded or you have to rush out to a fight, especially one nearby, but need a quick recharge on health and mana (health alone for Katarina).
Remember that it takes effect after having been out-of-combat for at least 6 seconds.

Aether Wisp = 850g
Amplifying Tome = 435g = 20AP
30AP = 653g
850g - 653g = 197g
For cost-efficiency, the 5%MS bonus must be worth at least 197g.

325g = 25MS
197g = 15MS

Considering Katarina's base MS of 345:
5% of 345MS = 17MS > 15MS
Considering standard MS cost to be worthy, Aether Wisp is cost-efficient even without having boots.


Luden's Echo:
Cost: 3000g
Using Needlessly Large Rod as reference: 60AP = 1250g
100AP = 2083g
Considering Katarina's base MS of 345:
10% of 345MS = 34.5MS = 449g
Maximum cost of special effect: 3000g - 2083g + 449g = 468g
468g = minimum of 110 (pre-reduced) damage to at least 1 target.

Comparison to AP:
468g = 22.5AP
Considering Kat's highest AP ratio non-ult ability, Bouncing Blades (60% considered):
60% of 22.5AP = 13.5 bonus damage
On ability casts alone, it takes 10 casts to reach enough charges for activation of the bonus damage effect of Luden's Echo.
If it worked with ability casts alone (no stacking from movement):
13.5 x 10 = 135 bonus damage which is higher than 110 but this is only considering the highest AP-scaling frequent-cast ability, which loses damage on subsequent targets hit, and considering movement not charging up Luden's Echo which is not actually the case.

Luden's Echo is therefore cost-efficient and even better than just focusing on straight AP for Katarina. The special ability is very effective.

Seeker's Armguard:
Cost: 1200g
20AP from Amplifying Tome = 435g
Using Cloth Armor as reference: 30 Armor = 600g
Total = 1035g < 1200g therefore the item is not cost-efficient at the time of purchase.
Total AP including all stacks = 35 = 761g
Total Armor including all stacks = 45 = 900g
Total with stacks = 1661g > 1200g therefore the item is very beneficial overall and is worth the purchase.


Zhonya's Hourglass as a one-time purchase:
Cost: 3000g
Using Needlessly Large Rod as reference: 100AP = 2083g
Using Chain Vest as reference: 50 Armor = 938g
Total = 3021g > 3000g
It is, therefore, a cost-efficient one-time purchase without even considering the bonus ability.

Consider upgrading to Zhonya's Hourglass after already having a fully stacked Seeker's Armguard:
Item Cost difference (not calculated value difference): 3000g - 1200g = 1800g
AP difference: 100 - 35 = 65 = 1354g
Armor difference: 50 - 45 = 5 = 94g
Total = 1448g < 1800g
Bonus Ability cost: 1800g - 1448g = 352g
Getting Zhonya's Hourglass via upgrade is a fair price but the value of Seeker's Armguard is greater individually. If the Stasis effect is not essential, Zhonya's Hourglass need not be rushed. For the balance of Armor and AP in a good deal, Seeker's Armguard is sufficient. It can be upgraded to Zhonya's Hourglass later in the match when other priority items are completed.

Rabadon's Deathcap:
Cost: 3500g
Using Needlessly Large Rod as reference: 120AP = 2500g
Bonus effect = 3500g - 2500g = 1000g
1000g = 48AP
For cost-efficiency, 35% of Total AP must be equal to or greater than 48AP.
35/100 x Total AP = 48AP
Total AP = 48AP x 100/35 = 137
The champion must therefore have at least 17AP besides that from Rabadon's Deathcap for it to be cost-efficient when purchased.

Spectre's Cowl:
Cost: 1200g
200HP = 533g
40MR = 720g
Total = 1253g > 1200g which is generally cost-efficient.
Although Kat doesn't utilize health as well as other champions, the item may still be costworthy especially after considering the special effect as well.


Crystalline Bracer:
It adds a 50HP difference from its components for the cost of 20g which is a good deal if the total costs of the health and regeneration are seen as worthy especially based on the champion.


Kindlegem:
Cost: 850g
200HP = 533g
10% cdr = 850g - 533g = 317g
It is cost-efficient if the health is worth the price and if 10% cdr is valued at 317g or more.


Banshee's Veil:
Cost: 2700g
450HP = 1200g
60MR = 1080g
+100% Base Health Regeneration = 360g
Total = 2640g
If the individual costs for the various stats are seen as worthy, it means that the special ability (spell shield) fills the remainder of 60g and makes the item cost-efficient.


Spirit Visage:
Cost: 2700g
400HP = 1067g
60MR = 1080g
+150% Base Health Regeneration = 540g
From Kindlegem, 10% cdr = 317g
Total = 3004g
If the individual costs for the various stats are seen as worthy, it means that the item is cost-efficient without even considering the special ability.


Banshee's Veil v.s. Spirit Visage:
Spirit Visage has higher Base Health Regeneration bonus by +50% but gives 50 less Health.
These are minor differences and if considered of equal value, they can be treated as cancelling each other out.
Apart from these, Banshee's Veil has the Spell Shield effect while Spirit Visage has the increased healing effect as well as +10% cdr.
The Spell Shield can be effective against critical spells such as high damage spells or otherwise deadly engages. Sometimes, however, the Spell Shield may be intentionally triggered by the enemy using a weak spell just to disable it before using a more powerful spell.
The cdr from the Spirit Visage helps Kat max out cdr and the bonus healing effect is helpful for survivability especially when paired with Spell Vamp.

I prefer Spirit Visage, but choose according to your own preference and playstyle.
You can even get both items. :) You just have to make a sensible judgment of how much Magic Resistance you need.

Hextech Revolver:
Cost: 1200g
2 Amplifying Tomes = 870g
12% Spell Vamp = 1200g - 870g = 330g

330g may be a worthy deal for 12% Spell Vamp. The Spell Vamp will be more effective with more damage.
It is not absolutely necessary early on especially as Health Potions, and even a Crystalline Flask, will be sufficient for health sustain.
I recommend getting this after completing Luden's Echo, Rabadon's Deathcap, a boots, as well as Seeker's Armguard and/or a Null Magic Mantle if needed.


Hextech Gunblade:
Bilgewater Cutlass by itself is not a great choice for Katarina. Hextech Gunblade overall though may be a helpful item for Katarina but it may be better to upgrade Hextech Revolver into it after completing other more essential items.
Although Katarina does not focus on basic attacks, the bonus AD from the Gunblade still adds damage to Sinister Steel and Death Lotus. The AD scaling on these abilities is also significantly higher than their AP scaling ratios.
Hextech Gunblade adds survivability to Kat through in-combat health sustain which enables her to last longer and repeat spells as she is designed for.

Cost: 3000g
Using Needlessly Large Rod as reference: 80AP = 1667g
300HP = 800g
Total = 2467g
15 magic pen + special effect = 3000g - 2467g = 533g
This item seems quite cost-efficient and may be effective for Katarina especially against enemies with high health.

Cost: 3000g
Using Needlessly Large Rod as reference: 100AP = 2083g
400HP = 1067g
Total = 3150g > 3000g
Considering the AP and HP worthy for their price, especially based on the champion, Rylai's Crystal Sceptre is cost-efficient without even considering its special ability.
This can be ok as an extra item on Katarina if there aren't better options. The slowing effect is not very significant on Kat since most of her abilities are multitarget which results in a lower slow % and duration. Kat also already has an ability to keep up to or get away from the enemy; Sinister Steel, which gives bonus movement speed instead.

Voracity:
More kills and more fight participation means more triggers of passive.


Bouncing Blades:
Target the unit desired to take the most damage first since the damage reduces for subsequent units.
Target closely positioned units for the blades to bounce and deal damage to multiple targets.
Sinister Steel can be used to hit all or multiple targets hit by Bouncing Blades to trigger the bonus damage in one shot.
Improve the damage of this ability with AP.


Sinister Steel:
Position Katarina accordingly to hit as many targets as she can with Sinister Steel.
Use it after Bouncing Blades to trigger the bonus damage.
Use it for the movement speed boost to chase enemies or run away from them.
Improve the damage of Sinister Steel with AP and AD.
This is a short-cooldown ability. In addition to cdr, build up Kat's resistance to last longer for repeated casts of Sinister Steel.


Shunpo:
Use it to engage an enemy, escape an enemy, gap-close, gap-extend, or dodge.
It can also be used to reduce the damage of spells or basic attacks within 1.5 seconds.
Its damage can be increased by AP.

Death Lotus:
Position Katarina accordingly to hit as many targets as she can with Death Lotus.
Do not activate Death Lotus if a nearby enemy has a disable off-cooldown (since it can stop the channel), unless Kat has cc immunity at the time and for a few seconds after to last the duration of the channel or a sufficient amount.
Use it appropriately against enemies before or during their healing effects to apply Grievous Wounds.
Improve the damage of this ability with AP and AD.

How to play against:

Voracity (passive)
- Simply avoid getting killed within 3 seconds of being damaged by Katarina.
- Help allies stay alive beyond 3 seconds of being damaged by Katarina.
- There may be a situation in which it seems that you’ll inevitably die even if you try to escape with something like Flash for example. If, however, it means buying a second or few to prevent activation of a Katarina’s passive that will enable her to kill an important ally or several, you may want to consider trading that flash for the save (Situational Analytics Level required: Pro).

Bouncing Blades
- Position your champion suitably to avoid getting hit by a blade or to get hit by a later bounce for less damage.
- If hit by a blade, avoid getting hit by a basic attack or spell from Katarina to prevent bonus damage.
- Blades can be blocked by Braum’s “Unbreakable” or Yasuo’s “Wind Wall”.
- Banshee’s Veil, Sivir’s “Spell Shield”, and Nocturne’s “Shroud of Darkness” can block the individual champion from the blades and prevent any further bouncing.

Sinister Steel (aka Dagger Spin)
- Position your champion suitably to avoid area of effect and prevent Katarina’s movement speed boost.
- Banshee’s Veil, Sivir’s “Spell Shield”, and Nocturne’s “Shroud of Darkness” can block the individual champion from the daggers’ damage but does not prevent the movement speed buff.

Shunpo
- Position your champion suitably to avoid unnecessarily being in casting range of ability.
- When so desired, prevent Katarina from being in range of blinking to any targetable allied or enemy unit including - Any allied or enemy champion, minion and ward
- Any Teemo ‘shrooms
- Any Rek’Sai tunnel entrances
- Her allied Demacian Standard
- Her allied Thresh’s Lantern
- Destroying enemy wards not only reduces enemy vision but also reduces the availability of targets for Shunpo.
- Damage can sometimes be strategically withheld for 1.5 seconds after Katarina uses Shunpo to avoid damage reduction. This may be especially useful for some spells and basic attacks with temporary buffs.
- Banshee’s Veil, Sivir’s “Spell Shield”, and Nocturne’s “Shroud of Darkness” can block the individual champion from Shunpo’s damage but they do not prevent the blink.

Death Lotus
- Channel can be interrupted by crowd control effects such as airborne effects, forced action, polymorph, silence, stun and suppression.
- Unless absolutely necessary, it may be strategic to withhold healing abilities until the end of “Grievous Wounds” if your champion has been hit by a Death Lotus dagger.
- Grievous wounds can be removed by Quicksilver Sash and Soraka’s “Wish”.
- Banshee’s Veil, Sivir’s “Spell Shield”, and Nocturne’s “Shroud of Darkness” can block only one dagger of the Death Lotus.
- Daggers can be blocked by Braum’s “Unbreakable” or Yasuo’s “Wind Wall”.


General:
- Increase magic resistance to take reduced damage.
- Magic Shields such as Morgana’s “Black Shield”, Kassadin’s “Null Sphere”, and the shields of Hexdrinker and Maw of Malmortius will mitigate all Katarina’s magic damage.
- Attack Katarina from afar if possible.

Fizz can use his Playful/Trickster to avoid damage from Katarina's abilities directly or by getting out of range.
Urchin Strike can sometimes also be used to get out of range of damage.
Be aware of this and whether these abilities are on cooldown before casting spells.

Katarina's Shunpo can be used in helping to chase Fizz or in attempting to escape, especially after Fizz has used Urchin Strike and/or Playful/Trickster.
It can also be used to dodge Fizz's ult.
If hit by the ult, Katarina can use Shunpo in a suitable timing to reduce the damage of the ult and/or for repositioning to prevent allies from also getting hit by the effects of the ult.

The channeling of Death Lotus can be interrupted by Fizz's ult. The delay for this interruption, however, is 1.5 seconds after contact so Katarina can at least deal some of the damage from her ult if necessary.
Judge the situation appropriately before using Death Lotus.

Spirit Visage and Banshee's Veil are helpful for Katarina against Fizz because of the defensive stats.
Banshee's Veil can be especially useful in blocking an undodged ult from Fizz.

If armor is needed, Zhonya's hourglass can be useful in preventing the effects of Fizz's ult.