Hi everybody !
First, i'm french, so sorry for faults.
It's my first guide, and i have chosen Jarvan IV. You'll may think i don't have much to learn to you, there are many guides about this char. But i'll do my best, i think it's the way to win.

Pros:
- Solid character, mostly with- Good dps
- Good harass
- Has an escape
- Great AoE slow
- Can watch in grass with his flag
- Knock up AoE
- Can easily make a gank, with flag + Dragon Strike, slow and cataclysm
- Can stay in the lane a very long time with


Cons:
- Can be targeted first
(i don't see anything else)

Why those runes ?
-Greater Glyph of Celerity: +8.1% CD reduction at lvl 18. Reduction is very important for jarvan: To harass and most of times, you will thanks your runes when enemies are flee and you catch them with your combo flag + dragon Strike.
I tried glyphes of focus, and at start it's not a must.

-Greater Mark of Desolation: +15 Armor penetration ! They will make you more damages !

-Greater Quintessence of Desolation: Same ! Now you have about 25 armor penetration.

-Greater Seal of Clarity: You'll need them at the end of the game.
At start, with Eleisa, you have all mana regen you need, but at the end, you'll sell it.

In a gank, if your enemy is knocked up, he'll be dead 3 seconds later.

Otherwise in a teamfight, don't engage. The tank comes, after, you knock all them up, and focus the squishy one. I don't give you advices, but DON'T hit the tank !!
Use your combo flag + dragon Strike + slow as soon as you can.

: Move faster to run away, get into battle, chase...
: 2 reasons:
- To finish an enemy who runs
- in a 1v1, against an ad, if he has lifesteal, at start you ignite, it works pretty well against Warwick, Xin etc. --->it limits life regen...and you cataclysm him to give you the "free" kill.

I take the shield at first. The eleisa let me use it all times, so i can't die.
After i take the flag for attack speed, and at the end the dragon strike.

Gank/TeamFight:++.

To harass, use your passive :
When you have mana use your combo :+++.

if your ennemy is fleeing, with low life AND WITHOUT FLASH, use cataclysm, care of flashes toward towers !!!

Not much to say:
- Last hit minions to gain gold.
- When there are ss, stay defensif. Better, you can jungle, near your tower: golems, maybe wolves but take care, put your flag into bushes !! You always have to use it !!!
- Kill minions in jungle as soon as you can, to gain more gold, and more exp. Moreover, ennemies will say "ss Jarvan !!", it's a good way to make them loosing some experience points, and sometimes...they can think i backed, and it's time for an allied to gank. But it sometimes happens.

-At start i take a. It will be usefull after for...

-. Back at 765 golds. Why ? To get Eleisa... Why ? It gives you all you need until end game. You can lane a long time due to life regeneration, and mostly, during all the party, you'll be able to cast all spells you want, when you want. It has a very good mana regeneration.

- I takefor AS
-for damages. Now you start to hit a little bit stronger.

No need life steal, you have Eleisa, you harass, take max damages, you stay defensif some seconds, and you regen all, your enemy will use all his mana on you but hopefully you don't care, because some seconds later, you are ready to continue farming, harassement etc.

- You'll need some attack speed. Take a. The bonus mouvement is great too.

- Now you need life steal, so take a. You will get some extra damages.

- Buy a. Now you have attack speed and some critic. Now, it's fun !

- You waited soooo long, to make great damages, take a. Now it's Very fun.

- For the last item, you have a choice. Take afor survivability orif there are an ad which is very annoying, otherwise take an other.

You should be very powerfull, annoying with your combo, and 3 shots squishies !