Kog'Maw Build Guide by Aqua Dragon
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+14 ability power or +8 attack damage, adaptive and +5.5% attack speed
Patch 8.7 Notice
Link to the latest iteration.
Hi! I’m Aqua Dragon. I was Diamond in Seasons 5 + 6, and I play AP Kog'maw.
I also play:
I also take people's suggested playstyles, optimize them, and then make guides on them!
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Pros and Cons
- Gets exponentially stronger as the match continues
- Prevents damaged opponents from fleeing fights
- Reliably farms creeps from a distance
- Able to duel anyone late game
- Powerful objective defender
- One of the best siegers in the game
- Atrociously weak early game
- Has low mobility
- Difficult laning phase
- Incredibly incredibly squishy
- Pathetic objective controller
- Neverending greed for mana
The Barrage Limit
Distributing Death in Moderated Concentrations
"Barrage Limit" is a term that will be repeated throughout the guide several times, and for good reason! It’s one of the most fundamental parts of playing AP Kog and impacts laning, teamfighting, and defending.
The ultimate’s mana cost goes up almost exponentially. Shooting 1 ult is a pitiful 40 mana, but shooting a full barrage of 10 bullets requires an enormous 2,200 mana.
This poses a problem. Continuing to fight requires constantly shooting, but constantly shooting drains mana. To maximize your time poking, you need to shoot just enough that your mana regen will have replenished more than the mana expended when your artillery stacks reset to 0, accounting for ult cooldown.
Or, more simply:
The number of bullets it takes to break equal with your mana regen is known as the Barrage Limit. The two examples above have Barrage Limits of 2 and 3.
It's a bit more than 10 seconds because the ult does have a 1-2 second cooldown between shots, and there's also time needed to line up the next shot.
Your Barrage Limit can be considered your guaranteed bullets. The rest of your mana bar is considered reserve bullets.
A final note: the Barrage Limit is not an exact science. You'll often find that you will lose 20-60 mana per barrage even if you stay at the Barrage Limit. However, it functions as a serviceable estimate. You can find out how to increase the barrage limit later in the guide.
Making the Rain Have Pain
There are a few extremely important, unintuitive things to keep in mind about AP Kog’maw for this guide to be of maximum effectiveness.
Scroll to the bottom of this section if you want the short version.
Kog Benefits Little From AP
AP Kog’maw is largely a misnomer. Unless you’re at full build, your AP levels will hover around 200-300 AP even 40 minutes into the game. Living Artillery has a fairly unimpressive 0.25 scaling on it. The AP scaling does increase as the target gets lower health, but then so does the base damage so it's kind of a moot point. This makes AP an underwhelming choice compared to simply increasing the Barrage Limit.
This isn’t to say Kog has bad ratios overall. The other abilities have fairly decent or even impressive attached ones. But AP Kog’maw is not dangerous due to their basic spells. If you’re looking for a mid-range AP champion, there are a wealth of others with significantly better damage, mobility, and utility.
However, your ability to consistently abuse this base damage is limited by the Barrage Limit. To take maximum advantage of magic penetration requires a high Barrage Limit.
Kog's Offensive Power Scales With Mobility
Hitting a person in a teamfight with one Living Artillery is easy. Hitting them reliably again is hard. The ultimate is designed to be entirely avoidable. Even if a champion is directly at the center of the ultimate, they are almost guaranteed to be able to run out of the AOE. If someone is running from you, they will outrun you as the casting time of the Ult prevents you from catching up.
To reliably chain ults on fighting opponents requires CC. To reliably chain ults on running opponents requires having more movement speed than the runner. Reliably chaining ults dramatically increases fighting power. However, when you hit the point where you can outrun opponents while ult’ing, any additional mobility encounters diminishing offensive returns.
Kog's Offensive Power Scales With Mana
As Kog gets more mana and mana regen, the Barrage Limit increases.
Every time you increase your Barrage Limit, you effectively increase your consistent damage output. Multiply the ult’s base damage by the Barrage Limit, and this is how much damage you can spread out in the ~12 second window before the ult resets the mana cost.
Each additional increase to the Barrage Limit is worth less than the one before. Having a Barrage Limit of 2 is twice as much damage compared to a Barrage Limit of 1, but increasing the Barrage Limit from 3 to 4 is only a 33% increase.
Unfortunately besides Tear, the mana regeneration options for mid lane are inordinately expensive. Mana regeneration needs to be sought out in other ways, primarily through killing Aqua Dragons and Blue Buff.
Presence of Mind Makes CDR Awesome
There is one rune that fundamentally changes the build priorities of AP Kog.
If you manage to land a single kill or assist in a fight, you can ult freely for 7 seconds.
The more CDR you have, the more times you can ult during that seven-second window. This suddenly makes items like Ultimate Hat and Archangels significantly more inticing. Having both of those can easily increase the number of ults in the window by 50%!
However, this CDR is more useful later, when teamfights are more frequent and you can regularly chain Presence of Mind into more hits.
tl;dr: Kog’s Build Priorities
The summary of everything above is that you should build Kog to take maximum advantage of the high base damage and range. The core philosophy behind playing AP Kog is:
One more Ult per teamfight, one more Ult on running opponents, one more Ult when defending.
This means the stats Kog generally wants more than anything else are:
This guide is built around this mantra.
Take note this means you won't necessarily have a lot of early-mid burst damage. But this is okay because you are a sustained damage champion!!! Always remember this. You will often get comments like "you don't do any damage." This is because it is extremely easy to overlook sustained damage compared to burst damage. You will almost always have one of the highest damages dealt in each match, so ignore these comments and focus on your aim.
Void Ooze has the most range, damage, and utility of all the basic spells, making it the first to be maxed.
Being in range to autoattack is too reckless as AP Kog, making the Q second to max.
- Just clicking on your opponent will often be sufficient to kill them even if they’re trying to juke the passive through bushes
- If you are running and about to die anyway, turn around. Fight. The passive may be able to turn a fruitless run into a revenge kill.
- Shreds a significant amount of armor and magic resist
- Use it when tanks commit to fights in the middle of your team
- After Rylais, it functions as an excellent peel tool
- Useful for farming, but little else for most of the match
- If you’re in range to autoattack, you’re probably too close to the fight.
- Late game, it can win you most duels and is amazing shred against tanky divers after applying Caustic Spittle
- Does not proc Rylai’s slow
- Your most reliable farming spell
- The slow scales with the level of the spell
- Fairly respectable damage late-game against bunched opponents when not peeling with it
- The keystone of AP Kog’maw
- Every level-up doubles Kog’s power and heavily increases range.
Kogulated Rune Choices
Comet is most useful for post-laning phase. Aery is less useful because the the ults arrive in windows, not constantly. Phase Rush is too hard to activate at useful times.
The Ultimate Hat
Ultimate Hat synergizes perfectly with Presence of Mind. Manaflow Band doesn't activate enough to impact the Barrage Limit.
Transcendence allows AP Kog to focus on more damage efficient item choices without losing out on CDR to abuse with Presence of Mind. More mobility is nice, but Rylais is usually enough for offensive power. AP isn't good enough on AP Kog to justify Absolute Focus.
Gathering Storm because the alternatives are worse. Scorch is for laning power, which AP Kog doesn't care about.
Presence of Mind
Presence of Mind is why you're going Precision.
Coup De Grace
Coup De Grace is the only other precision rune that works with AP Kog's goals.
There are too many flash-combos that even your max range can’t protect you from. Flash helps equalize the field, using flash to avoid dying to flash-combos
When flash is on cooldown, this is your second equalizer against flash-combos. It also prevents you from being towerdived by the mid and jungle. Later in the game, you are able to duel nearly anyone if exhaust is up.
Ghost is okay. Exhaust is better in almost all situations, but Ghost has use when with compositions that are explicitly structured to mitigate Kog's weaknesses and keep 'em safe even during the laning phase.
If you’re in range to Ignite, you shouldn’t be.
Priorities in Practice
At the beginning of the guide, we established the priorities Kog has.
Additionally, various AP items were evaluated by using my AP Kog'maw Damage Efficiency Calculator (TM)
The build order is the culmination of all that.
Elaborated on further down.
→ → → →
→ → →
Double Rubies are great lane survival; they are built into Guise and Rylais.
A Note About Components
Many of the items in this set have raw AP components like Blasting Wand. If you have a choice between using a final slot for a raw AP component vs. a control ward, go with the control ward. AP is a poor value choice on AP Kog, and stronger vision is more meaningful than a pittance of extra damage on the ult.
Doesn't Have a Nice Ring to it
The Problem with Potions
First, potions are not free. Each potion costs 50 gold, which is about 3 minion’s worth. Therefore, to have potions worth their cost, you need to get 4 more minions that you otherwise would have lost. Else, you are breaking even or worse, and the only gain is exp.
Second, Kog is so squishy that you can’t freely farm. Any decent opponent is going to be constantly harassing you away every time you try to move in to autoattack the minions. If you’re in range to be getting hit at all, you are not far enough. In addition, Kog’s early game is so weak that attempting to trade with people is an attempt in futility. You won’t be getting kills pre-6 unless your opponent is badly messing up.
These two facts combined mean that if you buy health potions, you would have to put yourself in poke-range and yet still manage to get 4 more minions that you otherwise would have lost. This doesn’t happen. Your autoattacks are too weak, your early range too limited, and your spells too infrequent to get 4 extra minions while standing in range of being hit.
Potions may serve useful when learning AP Kog, but they’re a needless crutch once you become proficient at farming from max range, especially because optimal play guarantees that you’ll run out of mana way before running of HP, even assuming you get hit occasionally.
The Problem with Doran's Ring
When you buy Doran’s Ring, you get it knowing that you’ll eventually have to sell it. The amount of money lost from buying and then selling it is 240 gold, or about 13 minions. To make the Ring worthwhile requires ultimately getting 14 more minions that otherwise would have been lost.
The AP component of Dorans is already negligible. Void Ooze, your primary laning ability, only receives a pitiful 7 damage increase. The AP increase will largely not increase your farming potential. AP also has little benefit for AP Kog later down the road.
Next, the mana component. Doran's Ring regenerates 1.08 mana per second, for a total of 324 mana over five minutes. Hitting 80% of the 69 spawned minions will result in 220 more mana, for a grand total of 544 mana.
To compare: Sapphire Crystal gives 250 mana. A long estimate for the first recall to refill on mana happens about 5 minutes into the laning phase. At level 5, Faerie Charm will provide 0.54 mana per second, for a total of 162 mana over five minutes. In total, the pair grants 412 mana over five minutes.
The question is now can you get 14 more minions, that otherwise would have been lost, with 60 more HP and 130 more mana compared to the Crystal start? Probabbblyy not.
130 more mana is barely one more Void Ooze, which nets 3 minions in a great case scenario. 60 more health might give one more auto of free reign, which is about 1 minion. That's looking at maybe 6 or 7 minions that otherwise would have been lost. At the cost of now having to delay the Tear rush and the Ruby Crystals.
Dorans is built with a purpose, and that purpose is to get an edge for the laning phase. For AP Kog, who doesn't care about trying to win the laning phase, it isn't as smart an investment compared to many other laners.
The Problem with Refillable Potion
As with Doran's, you buy knowing you sell it. 70 lost gold, so you need 5 more minions that you otherwise would have lost.
As mentioned earlier, Charm will regenerate 162 mana over five minutes. With Void Ooze and Barrage, that can earn about 4 or 5 minions. Really what is being asked is: can you get 11 minions that otherwise would have been lost with the extra health with refillable compared to the charm start? Actually... probably yeah. Refillable ain't too shabby. I wouldn't recommend against it.
But Here is where experience must simply take hold: unless messing up, I always run out of mana before I run out of HP. This means mana is a much bigger limiter on the number of minions able to be farmed rather than HP.
I wouldn't fault anyone for going refillable flask, and for most cases it is suitable. However, proper experience makes it a needless investment, one that extra mana is better able to suit.
It's one thing to say that AP is really poor on AP Kog, it's another thing to prove it. So let's do that, by first discussing damage efficiency, not to be confused with gold efficiency!
Gold efficiency only tells you how much gold an item theoretically costs while ignoring AP scalings, true damage, and damage patterns. This makes it a decent tool, but we can do better.
By using a calculator I've created for AP Kog'maw, it is possible to find the total damage of any set of spells / autos, which is divided from the gold spent. The Gold Spent For Each Point of Damage, also known as Gold/DMG, also known as damage efficiency.
This metric is significantly more useful; Rabadons may give the most raw damage, but it is also an insane amount of gold. What if Sorc Shoes provide half the damage at a third of the cost? Then Sorcs would be the better bang for buck.
The results? Magic penetration is absolutely amazing. There is no raw AP item that provides more bang for buck than magic penetration items on AP Kog'maw.
The following item choices were then judged on the damage efficiency metric.
A large mana pool is important to make sure reserve bullets are always ready later in the game. Tear also increases the Barrage Limit by 1.
A mixture of magic pen and mobility, a godsend for Kog’maw. It's tough to imagine any better combination that Kog would like.
Allows access to chaining, making your teamfight power significantly scarier; essentially boosts your mobility in offensive situations.
The most damage-efficient magic-penetration item for Kog’maw! It also grants a nice bit of survivability, giving it two applications in one.
Not particularly damage efficient, but an excellent way to get 20% CDR since you're building Tear of the Goddess anyway! The shield is a great bonus too.
The second most damage-efficient item for AP Kog'maw, though it doesn't grant any CDR. Build it if you need even more damage
Movement Speed and CDR; good priority stats for AP Kog! The Aether Wisp is also a much nicer component to have compared to some of the other items. Build if you only need a little more damage, or you get ample kills/assists in teamfights.
Because AP Kog barely autoattacks, Dead Mans functions as a permanent 60 MS boost along with some nice bulk. Use if you really don't need anymore damage
The common theme of this guide is that AP really is not that valuable on AP Kog. Rabadons exemplifies that; it is less damage-efficient than Liandrys, Void Staff, and Morellonomicon. It's a terrible buy in all practical scenarios.
Even with the magic pen, the damage efficiency is terrible, and it's far far too late at this point in the game to even consider Grievous Wounds.
If you’re in range to autoattack, you’re too close to the fight. The mobility may be nice, but Dead Man's would be better for the purpose while also increasing the offensive potential of the ultimate by far more.
The game will likely be over before you finish the shield, and damage efficiency is so terrible that it severely gimps your power. Twin Shadows is in a similar position, but at least that's paired with mobility and a good setup for future shots.
Magic penetration is higher on the priority list. Rylais is usually enough offensive mobility.
Upgrading Tear into Archangel’s Staff grants almost all the same stats, taking into account Seraph’s shield active which you quickly stack enough to get. RoA can't compete with the other items.
That's Off the Chain
When Kog has Rylais, they gain access to one of their most powerful and flashy tricks: chaining.
Chaining is using CC to ult a target back-to-back with Living Artillery.
Normally, chaining is hard. An opponent is able to dodge Living Artillery simply by stepping outside of the landing spot. But with Rylais, if Kog lands just one artillery, it almost guarantees that the next artilleries will land.
After landing the ult, continue aiming the ult a little ahead of the opponent’s running direction. This forces two decisions: get hit by yet another ult or momentarily stop.
Stopping is no safety. A person who has to momentarily stop has put themselves closer to Kog. If they stop sufficient times, Kog will be able to reliably land an ooze-spittle combo, killing wounded opponents almost instantly.
Stage of the Game
Kog is not defined so much by “early, mid, late” as many other champs as far as their role is concerned. Rather, Kog’s power and presence is dictated by the rank of Living Artillery.
Rank 0 - Feeble Mortar Mimicry
- Unless your opponent screws up, you will not win in CS.
- If you chose to not start potions or Dorans, your effective gold is higher than your CS would imply.
- Conversely, subtract CS from your opponent based on how many potions and Dorans they have.
- Survival is the name of the game
- Don’t bother pushing hard. Your autoattacks are like butter slapping a brick.
- If you die, you weren’t playing carefully enough.
Don't Bother Trading: It doesn’t matter if they’re melee, if they have less range, or even if they’re out of mana. Every spell, every auto should be focused on trying to farm above all else. Your kill potential is fairly nonexistent pre-6. If you think you can kill them by hitting them enough? That's precisely when everything will start going wrong.
Land Incidental Damage: You may not be trying to poke opponents down, but incidental damage is always nice. Try to position yourself to hit both the minion and the opponent at the same time.
Beware the Enemy Jungler: Kog is such an easy target for the jungler to jump on. This is the biggest reason why even poking is fruitless; a competent jungler will take advantage of your vulnerability even if you’re only a quarter of the way down the lane.
Beware Your Own Jungler: Survival is your primary priority. Unless you have a jungler with a mixture of heavy CC and heavy damage, consider informing your jungler to not even gank for you. Kills rarely result unless the jungler has red and you can land a well-timed void ooze or exhaust. But even this opens up the fight to a countergank that is easy to lose.
Go Back Instead of Pushing: Your pushing power is stupidly weak. Even two uncontested minion waves won’t bring the tower to half health. It’s not worth the risk unless their jungler is in a different lane.
Get a Control Ward Against Flanks: Get an early control ward and set it up to protect from a jungler tower-dive ambush. Good locations are the bush next to the Raptor camp or the bush across the wall near the tower.
Always Improve at Surviving: Every death is preventable. It means you were too far without wards, you were trying to trade, you didn’t dodge enough, or you got surprised by burst damage. Take every death as a learning experience of what to expect for the future and avoid repeating the same mistake.
Rank 1 - Obnoxious Spittle Tickler
- Prevent opponents from roaming
- Be cautious about roaming; it's often better to refill on mana
- Force squishy targets back with powerful ooze-ult combos
- If you die during laning, you weren’t playing carefully enough.
- Use your basic spells primarily for their utility
- Poke to deter
Ward the Enemy's Half of the Lane: Your opponent will likely have their ult at this point as well and will often begin roaming as you don’t have the pushing power to take advantage of their disappearance. Putting wards on their side of the lane will ensure that if they begin roaming that you will see which direction they go and your team will have heavy advance notice to get away. You have no pushing power to meaningfully punish roaming opponents
Be Careful When Following Roams: You may often want to chase after roaming opponents, but be aware that they may easily be hiding around a corner or in a bush in ambush, waiting to take advantage of your still-weak power. Alert your team, and be extremely cautious of ambushes if you choose to follow them.
Avoid Roaming: It's tempting to roam yourself, but you're usually better off just being more self-centered and farming up to Level 11. It may be self-centered, but it's not selfish, because it is the action that maximizes your entire team's chances of winning.
Use Ooze + Ult to Clear Minions: If you use Void Ooze on the caster minions, the execute bonus of the ultimate will become available on them, allowing an instant clear on the minions.
Deter Enemies With Ooze + Ult: Unless your opponent is very squishy, you should largely be using poke as a form of deterrence rather than a form of killing. Still, a successful ooze-ult combo on an opponent can deal substantial damage so always keep an eye out for chances to land one.
No Chaining Yet: Due to the low barrage limit at this point, and also because Rylais is often not yet completed, chaining is largely not possible.
Rank 2 - Artillery's Apprentice
- Keep everything constantly warded
- Clear waves instantly and begin pushing and grouping
- Be wary of dash-combos
- Poke to kill
You Probably Didn't Win in CS: This is okay. That's what you get when you play a champion with a weaker laning phase. Now is the time for the payback.
Still Ward The Enemy's Half: Your poke may be strong, but you still don't want the enemy roaming without warning.
Keep Mindful the Barrage Limit: Don't go trigger happy with ultimates. If a fight is about to begin, it is often smart to wait for it so that you can get several execution-enhanced ultimate shots on the enemies.
Use Spittle First: Caustic Spittle, Ooze, Ult, Auto. A committing target can’t avoid the Q, which will amplify the damage from the rest of the combo.
Chain Aggressively: Your teamfight presence is now massive even with few items. Your Rylais is often finished at this point, and now is the time to start chaining opponents down. Careful however; a wide variety of dash-combos can still reach you even at max range.
Scout With the Ult: Living Artillery grants vision on the location it casts on, so use it to see if the roaming mid-laner is trying to ambush you or if the opponents really are at baron.
Ult Your Feet: During duels against melee targets, keep ult’ing at the ground directly underneath yourself. This will guarantee the hit unless the target decides to disengage momentarily, buying valuable time to make distance.
Aim for the Zhonyas: Whenever you see someone has gone into Zhonya form, keep your eyes extra peeled on them and try to land an easy ult shot rightttt as the Zhonyas duration ends. Once you get good with the timing of your ult, the Zhonyas form is just a free target.
Rank 3 - Ruler of the Acid Reign
- Stay at max range unless you’re cleaning up
- Keep a target locked on and shoot
- Destroy diving opponents
- Poke to win
Abuse Your Range: You are now safe from almost every single dash-combo in the game at max range. Unless you are caught off guard due to poor warding, you cannot be reached except by flash-dash combos. Remain at max range unless it’s time to clean up, and continue buying constant wards to maximize your safety.
Caustic Spittle the Tanks: Use your Caustic Spittle to slow down and shred tanks trying to dive into the middle of your team. If combo’d with your spells right after, a few empowered autos is enough to deal insane damage.
Your Dueling is Good: Your dueling potential is extremely strong if you have exhaust up. If the fight is starting to die down, consider getting closer to the fight and pick off the remaining opponents with your basic spells, which now do fairly hefty damage in their own right.
Flash + Ult: Opponents will often try to break your chaining by flashing out of it. Flash toward them to immediately close the gap and continue chaining. Also use to get the last bit of distance to snipe a flee’ing opponent, but be wary that if they’re not CC’d, they can dodge the ult and waste your flash.
Use the Nexus Regen for Last Stands: In dire situations where you have to hold off several opponents from the nexus turrets, you are able to stand at the edge of the base regeneration and unleash a literally endless stream of bullets. This allows you to become the absolute final line of defense when things are looking grim.
Chain a Backline Target: You can safely pick targets every fight who you want to hunt down and chain them to death. Often, just a 3 or 4 artillery chain is enough to send an opposing magician to a quarter health or less for one final execution shot. Pick a target and keep them locked on.
Increasing and Exceeding the Barrage Limit
Making Good Impressions
The Barrage Limit has been mentioned several times in this guide, so now is the time to learn how to increase it.
Keep note that the Barrage Limit is not an upper limit on how many times you should shoot in a fight, but a general guide on how to maximize your consistent damage. As you play Kog more, the Barrage Limit starts to become more instinctual.
Barrage Limit starts at 0 and increases depending:
The highest amount your barrage limit can reach is 6
Raj of Barrage
There are times when it's time to stop holding back and go past the barrage limit. Blow out a full 10-ult barrage and cripple opponents... and yourself.
Realize that pushing past the barrage limit too much will make you useless for any further fighting. Be too reckless, and you won't even be able to dip into the mana refund needed to abuse Presence of Mind. As such, it makes sense that the barrage limit should only be exceeded when something can be secured or defended.
That can mean a several things including but not limited to:
- Securing a kill
- Securing an objective
- Securing a kill to secure an objective
- Keeping a small area scouted while taking a ward
- Defending a turret from low-health opponents
- Taking blue buff quickly, since the mana will regenerate
- Holding off opponents from defending an objective when it is almost dead
- Stopping a baron/dragon attempt
- Rushing a baron/dragon where your team plans to peace out after securing it
May your acid reign be endless.