Alright, you don't know me and I don't know you, but I'm gonna give you all my reasons for playing AP Windspeaker Tryndamere, and hopefully you will give him a try.

• His E, Spinning Slash has a 100% AP ratio
• His Q, Bloodlust scales off of 30% of your AP
• On top of the 30% AP scaling, Windspeaker's Blessing buffs his heal by 10%
• I was super high at the time (okay, not really)

Now keep in mind, this guide is heavily theory-based due to a lack of actual experience with AP Tryndamere. Also, for those who are interested there is a section with a bunch of math for damage and healing, so be warned. Make sure to take the information in this guide with a pinch of salt.

For runes, it's essentially what Tryndamere would typically run, although you're taking 3 Greater Quintessence of Ability Power instead of something like Greater Quintessence of Attack Damage

Marks

When I first started this guide, I was running 8 Greater Mark of Attack Speed and 1 Greater Mark of Critical Chance, however more recently I've been using 8 Greater Mark of Hybrid Penetration instead, so it's honestly a choice between Greater Mark of Attack Speed and Greater Mark of Hybrid Penetration. The example build that we will be looking at can easily get to the attack speed cap, so the Greater Mark of Attack Speed is unnecessary unless you don't plan on getting items like Nashor's Tooth or Berserker's Greaves. However, always get the 1 Greater Mark of Critical Chance because even as AP, lucky crits are pretty damn useful for Fury Stacks and reducing the cooldown on your Spinning Slash.

Seals

Greater Seal of Armor is the best choice, hands down. However, you can try using Greater Seal of Health, but I haven't tried that seal yet.

Glyphs

5 Greater Glyph of Magic Resist, along with 4 Greater Glyph of Cooldown Reduction is what I'd generally run on most my top lane champions.

Flash is something that works on every champion, and is also something you can combine with Spinning Slash in quite a few situations. The ones I can think of are Flashing in the middle of Spinning Slash, which you can do to catch an enemy who would otherwise not be hit by your E, as Flash does not cancel it. You can also use it to juke enemies near walls by Slashing one wall, then flashing back.
Teleport grants the extra mobility that every top laner needs, whether to get back to lane faster, or gank for your bot lane.
Ignite is very useful against enemies like Vladimir, Renekton, and Darius, who all have abilities that can heal them. Use Ignite to finish them off at the end of a fight, or stunt their healing in the middle.
Ghost isn't an ability that I use nowadays, although it serves a similar purpose to Flash. To me, running either Ghost or Flash is up to preference.

Or

Abilities

Battle Fury is your passive. It gives you 5 stacks of Fury for hitting an enemy, with either an autoattack or your E, 10 stacks for critically hitting, and 10 more stacks if you kill that enemy. So you can get between 5 and 20 stacks from one hit. Once you leave combat, you lose 5 stacks every 5 seconds. Also, for every point of Fury, you get +0.35% Critical Chance, up to a maximum of 35% Crit Chance at 100 stacks. The key to Tryndamere is maintaining your Fury stacks so that when s**t hits the fan you can whip out your umbrella.
Bloodlust is the reason why you run Windspeaker's Blessing . The sustain from Bloodlust is just insane, and it allows you to stay in lane for way longer than you could if you were running a boring AD Tryndamere. However, the heal isn't the only part of this ability. It also gives 5/10/15/20/25 AD, plus 0.15/0.2/0.25/0.3/0.35 AD per every 1% of missing health, so at your lowest possible health while ulting (70), you gain 59 bonus AD. Max this ability first for maximum sustain and bonus AD.
Be sure to use Bloodlust when you are at maximum Fury stacks so you can get the most healing done.
Mocking Shout is kinda meh, but it's still a good ability. It's an AoE debuff that reduces the physical damage of nearby enemies by a decent amount, and slows them from 30% to 60% (based on ability level) when their backs are turned. Both effects last for 4 seconds. Max this ability last.
If you're going against an AD champion, make sure to use this ability before trades, but be careful. Mocking Shout has a 14 second cooldown, so don't spam it as you will be weaker in the event of a gank without it.
Spinning Slash is your basic dash ability that deals damage to anyone in your path. Max this ability second.
Use Spinning Slash to dash over small walls, clear out creep waves, or use it in conjunction with Mocking Shout to get in front of the enemy and catch up to fleeing enemies.
Undying Rage is the reason why people hate him so much, regardless of their skill level, but for some pretty different reasons. Enemies hate it because he just can't be killed and is able to either escape a massive gank with a pixel of health, or take down the Nexus with everyone trying to kill him. However, allies hate it because he uses it to 1v5 under the enemies' Fountain turret. This ability is really easy to use wrongly, and knowing when to use it takes some time, as well as looking at other guides that can explain this ability better.

For AP Tryndamere, I run 12/18/0, making sure to take Windspeaker's Blessing

Ferocity

Fury or Sorcery

Honestly, both of them are equally viable, however I take Sorcery for more damage on Spinning Slash, which translates to more healing from Hextech Gunblade

Double Edged Sword or Feast or Expose Weakness

This should be self-explanatory, but in the case that you don't understand, then here's why you don't want Feast or Expose Weakness . Feast restores only 20 hp, and it also has a 30 second cooldown, which makes it kinda mediocre in a lane where you're almost always gonna be trading damage and need some form of decent sustain. Expose Weakness is just useless, unless you are a champion who is not designed to deal a lot of damage.

Vampirism or Natural Talent

So far, I've only been running Natural Talent for more scaling on my abilities, however I have not yet determined how Vampirism would fit into the build. If I find out, I'll edit it into this section.

Bounty Hunter or Oppressor

This is kind of obvious for me, since Oppressor works very well with Tryndamere's Mocking Shout. Of course, if you plan on just steamrolling the enemy, then Bounty Hunter will give a much better bonus, as long as you can kill at least 3 enemies. At that point, the damage boost from Bounty Hunter is superior to Oppressor .

Cunning

Wanderer or Savagery

Since you're going to be spending a lot of time in combat, especially in the laning phase, the damage buff from Savagery is a better choice than the out-of-combat movement speed buff from Wanderer

Runic Affinity or Secret Stash or Assassin

This mastery tier is pretty simple. You won't need Runic Affinity since you won't be going after jungle buffs for most of the game. Secret Stash is technically viable, however I do not recommend it since the heal from the base Health Potion combine with the heal from your Q is more than enough sustain. I personally take Assassin for better damage in lane, although this will not be as useful in the late game, especially in team fights.

Merciless or Meditation

This isn't even an option. Mana regen is useless on Tryndamere

Bandit or Dangerous Game

This choice is entirely situational and based on who you're laning against (at least, that's how I see it). If you're against someone who can zone you out and prevent you from last hitting, then go with Bandit . Otherwise, your default mastery will be Dangerous Game .

Precision or Intelligence

You honestly don't need 45% CDR on Tryndamere, since your cooldowns are pretty decent by late game, assuming you get 40% CDR from your items by then. With 40% CDR your cooldowns are reduced to 7.2 seconds on your Bloodlust, 8.4 seconds on Mocking Shout, 5.4 seconds on your Spinning Slash (which gets reduced even further by crits), and 54 seconds on Undying Rage.

Stormraider's Surge vs Thunderlord's Decree vs Windspeaker's Blessing

Okay, first I'm going to give a brief explanation of what each of these do, in case you don't like looking at the numbers from the official descriptions.
Stormraider's Surge : If you burst an enemy hard enough within a couple of seconds, you gain bonus movement speed and slow resistance.
Thunderlord's Decree : Damaging an enemy 3 times causes Zeus to bonk that enemy on the head for magic damage that scales mostly with AD, and a bit of your AP, however it has a cooldown so you can't taser multiple enemies in succession.
Windspeaker's Blessing : Buffs all your heals and shields. Healing/Shielding an ally gives them bonus Armor and MR.
Now, why do we go with Windspeaker's Blessing ? Because of the 10% buff on your Q. I will go into the math in a separate chapter, for those who are curious, but TL;DR, Windspeaker's Blessing increases the heal by 116 health at level 18, with the example build (which gives 579 AP). While 116 health might not seem like a very significant increase, I feel as though every extra point of health matters, thus making Windspeaker's Blessing worth it in my mind.

Alternate Keystones

Now, if you aren't one to worry about that increase in health, then the other keystone masteries in the Cunning tree are all viable, and in the end it comes down to personal preference. Of course, if you want to put more points into Ferocity, then that also works. In that case, you can put 5 points into Battering Blows , and for the keystone in that tree, you can choose between Fervor of Battle and Deathfire Touch .

Starting Items

This is your first option when you're going into lane. If your opponent is someone who deals a large amount of AD, then get a Cloth Armor and build into a Seeker's Armguard.
You'll seriously need this since your heal is at its weakest point.
Ward regularly, watch out for ganks, you know the drill.

Components

Always try to get this item on your first back, as it builds into Guinsoo's Rageblade.
If you have enough gold after buying a Blasting Wand then buy this.
If you'd rather start building Nashor's Tooth, then build this item after a Blasting Wand
If you buy a Blasting Wand, and you want a Nashor's Tooth, and you don't have enough gold for a Stinger, then buy this.

Core Items

Riot seems to have nerfed the AP bonus on this item, but it is still ridiculously amazing. The highlight of Guinsoo's Rageblade is now how when you get to 6 stacks on its passive, all on-hit effects are activated twice on every other autoattack. When you combine the on-hit magic damage on Guinsoo's Rageblade, Nashor's Tooth, and Wit's End (if you end up getting that item), as well as the passive 15% health per damage gained from Hextech Gunblade, you become an absolute beast.
Getting this item after Guinsoo's Rageblade should be a priority, right after getting boots. This provides a lot of AP and a decent amount of AD, making it another necessity on hybrid builds, but the best part is that it heals for 15% of all damage dealt, so you can heal off of your Spinning Slash for quite a bit, but how much can you heal from it? (Find out in a later chapter on the math)
Are you seeing a theme with these core items? Well if you can't it's the fact that they all give a nice amount of AP and have some sweet on-hit effects.

Next Items

This is a pretty good item if you're going against a champion who deals a lot of Physical Damage. On top of the AP and Armor you get from Seeker's Armguard, it also gives you +15 AP and Armor after killing 30 units (0.5 of each, per unit killed). This also builds into Zhonya's Hourglass.
This is a really good item for AP Champions in general, since it offers AP, Armor, and CDR, all of which are very useful on someone like Tryndamere.
+60 AP and MR, as well as 10% CDR? AND it decreases the MR of enemies around you? This item is incredibly useful if you already have your core items, or if you are laning against an AP champion like Ryze or Vladimir. However, this item does fall off during the late game, so sell it when you feel as though it's losing effectiveness.
This thing... This freaking thing. I highly recommend against buying this item unless the primary damage of the enemy team is Magic Damage, since it makes a minion permanently immune to magic damage, while also buffing its stats. Note, however, that you cannot buff super minions (because that would be stupidly broken and OP).
A 10% movement speed buff and 100 AP makes this item incredibly useful for Tryndamere. Just run around and then E in order to deal tons of damage. This effect also works well with Rylai's Crystal Scepter in order to slow multiple enemies.
This is a really good item since it lets you slow enemies with your Spinning Slash, and slows enemies again with the proc from Luden's Tempest.
Wit's End seems like a strange choice, however you have to understand that this is yet another item that has some sweet on-hit magic damage, as well as an effect that steals MR from your enemy, making them more susceptible to your attacks.
A fair amount of AP, 10% CDR, and some health make this a pretty good item, especially if you want to get to 40% CDR. (Math for its Active in the Math Section)
I highly recommend this item as the last item of your build, since it gives so much AP and it makes your abilities way stronger.

Boots

Get these for the attack speed
Get these if the enemy has a lot of AP and CC

For this section, we will be assuming that we have the example build, in which case we have 540 AP. Assuming we have 6 stacks on Rageblade's passive, then we will have 564 AP.
Secondly, the term "modifiers" will be used. This term refers to Armor, Magic Resistance, Armor Penetration, and Magic Penetration, because that's some arithmetic that I do not want to look up.
Keep in mind that, due to these modifiers, much of the damage calculations will be off by quite a bit, so when I say that "Ability X will deal Y amount of damage", don't expect to deal that exact amount of damage.
Lastly, the specific formulas and equations for this stuff can be found on the wiki.

Math for

Without Windspeaker's Blessing , Bloodlust will heal according to this formula:
70 + 30% of AP
This results in the following:
70 + (0.3 * 579 AP) = 243.7 health from the cast
Then we can add the health gained from the 100 Fury stacks, which is calculated 2.3 (+1.2% of AP)*100 stacks. At 579 AP, the health gained from 100 Fury is:
(2.3 + .012 * 579 AP) * 100 stacks = 924.8 health from Fury stacks
This leads to a total of 1168 health.
Since Tryndamere starts out with 626 health and gains 98 health per level, if Tryndamere is at level 18 by the time he gets his full build (which leaves him at 2292 max health), you can potentially heal 51% of your maximum health, which is just ridiculous.
However, when you add in Windspeaker's Blessing , that heal gets buffed by 10%, so the heal now becomes
1168 + (1168 * 0.1) = 1284 health, or 56% of your max health. Essentially, Windspeaker's Blessing buffs your healing by 116 health.

Math for

At its maximum rank, Spinning Slash deals physical damage according to the following formula:
Damage = 190 + 100% of AP + 1.2 * bonus AD
With our 579 AP and 152 bonus AD(if we count 6 Rageblade stacks, and assuming you are at 70 hp, which means that you are missing 97% of your max health), this damage is:
190(+100% of 579 AP)+(1.2*152) = 951 Physical Damage before modifiers
When we combine this with the 15% heal from Hextech Gunblade, we get:
951 damage * 0.15 = 142 health gained

On-hit Math

Alright, so one of the reasons why you could opt to take Greater Mark of Hybrid Penetration over Greater Mark of Attack Speed is this s**t. With the items in your build, you will be dealing a lot of magic damage in your autoattacks so let's take a look at that.

• Guinsoo's Rageblade has a passive that deals 15 magic damage on a basic attack.
• Nashor's Tooth deals 15 + (15% of AP) as magic damage on a basic attack
• Wit's End deals 40 magic damage on a basic attack
• Hextech Gunblade heals you for 15% of all damage dealt

We can ignore Wit's End for the purpose of simplicity and stick with the example build. with 579 AP and 152 bonus AD (which totals to 268 AD), which we can use to determine how much total damage we deal on a basic attack.
Without any modifiers, our basic attacks deal 268 damage
The magic damage (before modifiers) dealt is 15 + (15 + 15% of AP), so:
Magic Damage = 15 + (15 + 0.15 * 579) = 117 damage.
Thus, the total damage is 385. Therefore the healing on a normal basic attack is:
0.15 * 385 = 58 health.
However, on every other basic attack, Guinsoo's Rageblade procs all on-hit effects twice. So, every other basic attack will deal 770 damage before modifiers. Not only that, but the heal from Hextech Gunblade will likely be proc'd as well. In the event that the heal is proc'd twice, then the amount healed is as follows:
2 * (0.15 * 770) = 231 health gained.
However, if it does not proc twice, then the amount healed is simply:
0.15 * 770 = 115 health.
Of course, knowing how much you're healing from a single autoattack isn't very helpful, so let's look at how much you can heal per second.
Tryndamere's base attack speed is 0.67 attacks per second. At level 18, his attack speed is about 1 attack per second.
Since the attack speed bonus from items is additive, we have to calculate the attack speed given by every single item, component or otherwise, in Tryndamere's final build. Also keep in mind that the attack speed limit is 2.5 attacks per second.

• Dagger gives 12% bonus attack speed (we have 5 in the build)
• Berserker's Greaves gives 35% bonus attack speed
• Recurve Bow gives 25% bonus attack speed
• Guinsoo's Rageblade, at 6 stacks, gives 48% bonus attack speed
• Stinger gives 35% bonus attack speed
• Nashor's Tooth gives 50% bonus attack speed

So with those values, let's calculate how much real bonus attack speed is in each full item by adding the attack speed of its components + its final bonus.

• Berserker's Greaves gives 12% + 35% = 47% bonus attack speed
• Guinsoo's Rageblade (at 6 stacks) gives 12% + 12% + 25% + 48% = 97% bonus attack speed
• Nashor's Tooth gives 12% + 12% + 35% + 50% = 109% bonus attack speed

So we just have to combine these percentages to get 253% bonus attack speed from items.
Therefore, Tryndamere's total attack speed at level 18 would be
1 * 2.53 = 2.53 attacks per second.
This brings us to the attack speed cap of 2.5 attacks per second
If we multiply the attack speed by the health gained per hit, then we get:
2.5 attacks per second * 115 health per hit (before modifiers) = 285.2 health gained per second. But this is not including the health from every other autoattack from Guinsoo's Rage, so we have to figure out how long one attack is.
Since every second there are 2.5 autoattacks, that means that one single autoattack takes 2/5 of a second, or 0.2 seconds. However that isn't very helpful, so we can rewrite that as being 5 autoattacks in 2 seconds as a cleaner visual.
We know that in 2 seconds, Tryndamere does 5 autos. Therefore, he has 3 normal basic attacks, and 2 Rageblade-enhanced attacks. This means that the health restored every 2 seconds is:
(115 hp restored * 3 hits) + (231 hp restored * 2 hits) = 807 hp every 2 seconds.
And if we divide that by 2, we can get the health restored per second, which is 403.5 health restored every second. With Tryndamere's maximum health of 2292, you can heal up to max health's worth from about 6 seconds of straight autoattacking, assuming you aren't being bursted down.

EDITS

Patch 6.11

• Reduced the attack speed of Stinger to 35% from 50%
• Attack Speed of Berserker's Greaves buffed to 35% from 30%

Early/Laning Phase

This phase is all about putting the "sus" in sustain.

At level 1, just last hit. If you think the enemy laner is going to try and bad-touch you, then E to safety and keep at it. If you take some damage then use your Health Potion and try to stay out of trouble for the most part. A good tactic is to autoattack the enemy laner, and immediately follow up with an E away from them, and preferably through their minion wave. This allows you to get a good amount of stacks, and potentially clear an entire wave if the minions have low-enough health. Otherwise, you can simply use it to pick off any minions that you wouldn't be able to reach by simply walking.

Once you hit level 2 and you have your Bloodlust, you can start playing a little more aggressively now that you have your sustain. At this point you should focus on maintaining 100 Fury stacks in the event that you get ganked or a you lose a trade and need to heal..

After level 3, your W will allow you to do much better in trades, especially against AD champions. However, until you get to level 6, and thus your ultimate, you will still need to be very cautious. Typically, you W them, autoattack them one or two times, then E out when it becomes risky to continue.

Once you hit level 6, you can continue playing aggressively, but you will still need to ward heavily and watch out for ganks. Don't go all-in unless you are completely sure you can kill the enemy laner without dying. Even with your ult, if the enemy laner is someone like Teemo who deals Damage over Time (DoT), or has Ignite then you will need to be very careful as they can Ignite you when you are at very low health and prevent you from healing enough to save you.

After Laning

Will add this part later

Well this is my first serious guide and it took me forever to make it. I am incredibly sure that there are a lot of spelling/grammatical/mathematical/mechanical errors, so make sure to point them out so I can correct them!
Also, if there are any questions that you would like to ask about this build than feel free to tell me and I will try to respond to the best of my ability.
I will be regularly updating this guide as new patches are released, as new information is given, and when I feel as though updates are necessary.

Thanks for giving this guide a read!