Thornmail Jarvan IV Build

1. You rush Thornmail and stack as much Armor as you can.
2. You become auto-attackers' worst nightmare.
3. Hit or miss. Works great if the enemy team is full of physical damage and auto-attackers. Less effective against full AP - but still viable since players auto attack anyway.

Getting started

1. Start with Bramble Vest and Ruby Crystal. Rush Thornmail #1, then keep stacking Armor items.
2. This build is aimed to counter AD comps. Since you don't know the enemy team before loading in, you need to adapt. If they are heavy AP, you can just fall back to a regular tank build.

During fights

1. Stay in the middle of fights as long as possible. The more enemies hit you, the more damage Thornmail reflects.
2. If you manage to proc Aftershock during the fight, you are gonna deal tons of damage from Thornmail, try keeping it for it, if you can.
3. Randuin's Omen is great for engagements - it slows enemies on activation and reduces their crit damage.
4. Late game, you can consider selling boots for a 6th item - for even more sweet Thornmail damage!
5. You can use Bandlepipes to give your whole team an attack speed boost whenever you CC enemies. Great synergy with auto attackers.

Runes

1. Be careful to not waste Aftershock. Try timing it and keeping it for going in. It increases your Armor greatly, which in turn increases Thornmail damage!
2. You can also take Grasp of the Undying as an alternative rune if you prefer scaling.
3. Triumph is better overall (heal + gold), but if you want to have easier time with your mana, go Presence of Mind.

1. Golden Aegis (W) can trigger Fimbulwinter, so be careful to not waste the proc!

Martial Cadence (Passive)

1. Switch targets often in fights to fully use your Martial Cadence (Passive) for more damage!

Dragon Strike (Q)

1. Remember that your Dragon Strike (Q) reduces enemy armor. Shred tanks so your team can melt them faster.
2. With enough Ability Haste, you can Q to same Demacian Standard (E) twice!

Demacian Standard (E)

1. You can use Demacian Standard (E) for brush control.
2. Remember that Demacian Standard (E) gives Attack Speed buff for your allies, it is very important when pushing turrets or in teamfight (when you can't participate)
3. Jarvan can achieve 100% kill participation simply by placing Demacian Standard (E), thanks to its AoE aura for allies that grants assist even without any damage or CC.

Cataclysm (R)

1. You can Cataclysm (R) enemies and then run away to your team with Demacian Standard (E) + Dragon Strike (Q). This way you can engage for your team, pin enemies and be safe.

Combos

1. Combo #1: Q + E + Flash. Just Q + E and during the last frames of animation, you can Flash into enemy knocking them up.
2. Combo #2: If you have enough Ability Haste, you can put E, wait and Q to it and cast second E hitting your target. This is especially cool with AP builds. So you can cast E while sliding to existing E.

1. You can use the Dragon Strike / Demacian Standard combo to get out of your own Cataclysm arenas.
2. Split your basic attacks on different champions at the beginning of fights to maximize damage.
3. Use Demacian Standard as a scouting tool when worried about incoming enemies.