Welocome to my first MOBAFIRE Guide. It's about Jarvan IV, one of my main Champions in the League. By the way, i'm from Germany, so please dont flame about my Grammar or spelling mistakes.
At first I want to say, that Jarvan could be played as a physical DPS champion or a jungler, but this guide is about "Tankvan IV". So pls search for another guide, if this one doesn't compares to your playstyle.

This Rune-Setup is my favourite one. It gives u early Game sustainability and gives you extra health in the late game teamfights. You can change the Armor Pen. Quint. and Marks into extra health or armor, but I prefer Armor Pen. for the little amount of damage u can make when your jungler is coming to gank.

Well, the first item u will buy is a Cloth Armor and 5 HP Pots, because u will usually play against an AD Offtank on top. If u play against an Akali, you'll need to buy a Null-Magic Mantle and 2 HP Pots, for the early Magic Resistance.
The first main item I rush is the Frozen Heart. I gives u a lot of mana and Armor AND reduces cooldowns. Great because of his ultimate.You'll jump more times on the supporter or AD carry on the enemy team.
Of course ur shoes will be the Mercury Treads. They give u a little bit of MR and of course the Tenacity effect. How i think, a must have on the tank.
The third item is the very often used Banshees Veil. It gives u MR,Mana and Life, and the bst thing, it blocks every minute 1 skill by the enemy! Great item, a "must-have".
The forth item is the Thornmail. What's so special about this item? It gives you 200 Armor (!) and the AD enemies, will take 30% of their damage by themselves! Isn't this great?
Now u want to build a Guardian Angel OR a Randuin's Omen. Puh, i dont know which one i prefer. Both items are pretty nice. The Guardian Angel gives u Armor,MR AND a great passive, which allows u to revive after u died with a little amount of health and mana. Randuin's Omen has a active ability, which slows the movement- and attackspeed of the enemies. Great to use it for a chase or to gtfo! ^^

Pros
- great Initiator
- natural espace combo
- heavy tank
- epic stun

Cons
- early game Mana problems
- not that high damage with this build
- u won't get any kills (kills = better for your carry)

Well, the early game is pretty similar. U want to lasthhit a lot, to harrass the enemy a little bit and wait for ur jungler to gank. Here comes the Jarvan solo top bonus! U can stun the enemy with your E+Q combo, and,if needed, dont let him get away with your ultimate. Actually a free kill, if Flash is on CD :p
If teleport is ready, u actually can come bot or top for a quick gank, if ur minions r a little bit pushing.

Now u have a lot of armor and MR, so u can engage into the enemy team, knock them up and use ur ultimate to not let them escape! If u get into an silly situation, use flash or E+Q to get away. Usually u will get focused, because u will stand inside the enemies and take their skills, so your team can focus the enemy carry or supporter.

How i think, the best phase in the game! U will have a lot of MR,ARMOR and Health. Try to play passively, but if u see the supporter or carry in a beautiful situation to catch him, do it!
One E+Q combo, and,if needed, ultimate and ur team will get him down. The enemy team will follow him, so focus the next most important target! The supporter. Knock him up as often as u can, and save ur teammates. If u will die, it won't be that bad! Maybe ur team will ace them, and u win :)

How i think, the best are Morgana and Urgot. Morgana could stun one enemy and u'll just jump in and stun them how often u can. Jar's ult and Morganas are perfect.Urgot's ultimate works great with Jarvan's too. In the Phreak champion spotlight it's shown too, just watch it and you'll see :)

Maybe he is not the best tank or solo top char, but i think his initiations make him so unique. He is really hard to kill, and can help his team very well, especially carry if ur teammates focus the right enemy ^^

So, i hope this guide could help you a lot with the "Tankvan IV" and I really suggest you to buy him. He's great and a lot of fun to play!

Thank you for your interest ! :)