Good day!

What's that I hear you say?

Tryndamere mid?? BLAAARRGGHH! Is this some sort of jest?

Why, not at all, good sir or madam, not at all. Tryndamere excels in the mid lane for several reasons:

He needs a lot of farm, as can be found in mid.

His crits will melt a squishy mage.

He has enough sustain to survive the poke.

The element of surprise!

Just follow this guide, and watch as the chat log fills up with rage and despair from their mid champion.

Warning: This guide is for professional infuriators. May induce tears and/or ragequitting from the enemy team.

Pros:

Awesome ultimate Undying Rage
Great farmer
Extremely high damage with full fury
Mobile with Spinning Slash
Complete jerk in lane



Cons:

Kited easily
Can be caught by cc and nuked before using Undying Rage
Quite farm-reliant
No ranged poke

Ideal:

Ghost : Amazing on Tryndamere. Allows him to keep hitting them with basic attacks as they run away. Couple this with Mocking Shout and Spinning Slash and they ain't going nowhere.

Ignite : Good for early game duelling. Ignite them as they start to fight you and they'll have no choice but to run away (to an early grave).

Alternatives:

Flash : Obviously useful as an escape tool/gap-closer. Once it's used, though, you'll be at normal speed again.

Exhaust : Mocking Shout not enough for ya? A good alternative to ignite, slowing your opponent drastically and limiting their damage.

Teleport : Useful for getting back to lane quickly, or for ward-ganking other lanes. As Tryndamid though, you shouldn't be forced out of lane too often anyway.

Battle Fury : A pretty awesome passive, enabling Tryndamere to get a 35% increase in crit chance with full fury. Basically, make sure fury is full before charging in, otherwise you won't have the damage to make it count.

Bloodlust : Use this to heal up if necessary, but bear in mind it consumes your fury as you do so. Take it early for the extra passive AD.

Mocking Shout : A nice slow when the enemy's back is turned away from you. Use it anyway when duelling to limit their damage if you're in a pickle.

Spinning Slash : Your escape/gap-closer. Use it to engage your opponent, or run away when the going gets tough. It can usefully be used to escape over walls.

Undying Rage : The ability that defines Tryndamere in many eyes. Makes you invulnerable for several seconds, enabling you to escape or continue the fight. Make sure you use it just as you're about to die, otherwise you might as well save it.

Tryndamid really relies upon being an absolute jerk in lane. I mean it. A really nasty person.
Having to fight an AD mid as an AP carry can be upsetting, so you have to capitalise on this.

At level 3, with full fury, Spinning Slash into your opponent and just whale on them!

They'll have to back off sharpish, especially if they've already used their abilities. Use Mocking Shout to slow them as they run and keep hitting them .

Rinse and repeat often. At level 6, feel free to towerdive with Undying Rage (assuming they're low enough). Kill them, Spinning Slash out of there and Bloodlust to gain back some health. Simple.

Hopefully, by being such a lane bully you will have already limited the use of their mid champion (presumably an AP carry) in team fights.

Your role as Tryndamid is to destroy the enemy carries. Wait for your team to initiate, then jump in and hack away. Using Undying Rage to gain precious seconds while finishing off their carry might just be worth it to secure victory for your team.

Tryndamere also excels at splitpushing, particularly because of his high crit chance and attack speed. Use Ghost and Spinning Slash to escape when the enemy realise how close you are to their inhibitor.