Disclaimer: This build is not meant to scorn anyone elses builds, This is how I Dremu have been playing Jarvan IV and it's been working out for me, This is not to be better than any other build or show that others do not work, This build is only meant to help you learn to play your champion in the most efficient way possible.

Summary:

If you were smart enough to actually read this whole guide instead of just observing the top, then you should be able to play Jarvan with some more knowledge than you had of him before. Note that I am not making this guide to say I am an amazing player at this champion, I have played enough matches with him to learn how he is played however.

Pros and Cons

Pros:
1. Tank Slayer
2. Long life
3. Great DPS
4. Great ArP
5. Good Support skill
6. Aggressive Early game

Cons:
1. Slow midgame
2. 1 Ranged ability (small range)
3. Still new
4. 1 Cool Skin :(

For the masteries I chose for Jarvan to have a hybrid of Offense and Defense, For the reason that he is a tank/DPS although he may not seem like it, He is actually meant to be a tank denier. He will have everything he needs to easily take out a tank or just take out the weakest link.

Greater Mark of Desolationx9 This mark is great for Jarvan for the extra ArP, Jarvan IV is a great ArP stacker.

x9 Fort seals are great for Jarvan to help him out with the early to late tanking, increasing his health and making him not need as many health increasing items.

x9 Warding glyphs are awesome for the fact of the magic resistance to help him in magic fights to tank against them more efficiently.

x3 3 quintessences of Fort will once again help with tanking, But also the health does help with taking out tanks so that you can last long enough to end them before their team ends you.

Mercury's Treads are the first completed item for Jarvan IV, These boots can be taken or replaced by Berserker's Greaves depending on your situation, If there is more magic casters take the treads if there is less and less CC as well take the greaves so you can get some extra AS.

Frozen Mallet is what will start him off in the tanking area, This gives him his health and also his AD, and of course as you all know the slowing attack as well.

The reason for choosing Youmuu's next is obvious, it gives Crit strike, AD, ArP, CDR and also AS and MS when activated. So that makes this a very good weapon for Jarvan IV for many reasons.

Sunfire cape is great for Jarvan IV for the health armor and the extra damage it does a when near enemies, which could seem like it does nothing but it's like invisible damage, it happens in the backround but it could have gotten the kill for you. This could also be replaced for Force of Nature incase you need the magic resist.

Infinity edge is next for the AD and Crit, the passive makes it very nice too, This weapon could be replaced with for Madred's Bloodrazor which will make you an even more of a tank killer, But if you want the extra AD and Crit go with Infinity's edge it basically depends on how tank heavy the team is.

Atma's Impaler is a great asset to Jarvan IV for the fact of the extra armor, Crit strike and 2% of your max health as dmg. I would not suggest replacing this item.

There is not "Situational Item" Section this time, for I put every item you should replace with if wanted to up there ^^ If you come up with any other item replacements however let me know and I will probably put it up.

Now for the skill section.

Jarvan IV exploits his target's opening, dealing 8% of the target's current HP as magic damage. This effect cannot occur on the same target for 6 seconds.

This is one of my favorite passives, It can really turn a fight around in the first strike, also if you got Madred's Bloodrazor then that makes it 12% damage done in one strike, Making that item amazing for this passive, But only recommended in certain situations.

Jarvan IV charges through his opponent, dealing physical damage and lowering their armor by a %. This will pull Jarvan IV to a Standard if it encounters one, knocking up all enemies in his path.

This is your Q ability and is your most important one, This ability can get you out of harms way or completely harm an enemy, It's great for the fact of it penetrating the enemies armor and doing a nice amount of dmg +AD.

Jarvan IV calls upon the ancient kings of Demacia to shield him from harm and slow surrounding enemies. Triggers automatically if damage would reduce Jarvan below 300 Health if it is not on cooldown.

Golden Aegis is a great tanking ability, increasing his health without activation or while activating, making him a tanking machine and very hard to bring down.

Passively grants Jarvan bonus attack speed and armor. Active: Throws a Demacian flag, dealing physical damage and granting passive benefits to nearby allies.

This standard is very good for support, it increases your AS and armor making you the DPS tank you are, also when used it gives that passive to your allies, giving them an opportunity to survive or help do more damage with the AS.

Jarvan IV heroically leaps at his target, dealing physical damage and creating a circle of terrain around them for a few seconds.

Jarvan IV's ultimate is Cataclysm this forms an arena around you and an enemy (or more enemies/allies) making it unable to escape without Flash or a teleport spell, Or another skill that kick you out of course. This ultimate is NOT OP so don't say it is, It is annoying to be caught in it but it can easily be countered, Also you can easily kill Jarvan whom cannot escape unless he is smart enough to jump out or deactivate it.

There isn't much of a skill rotation but I go with this.

Q,E,Q,R,Q,W suggested for escape methods E,Q (E for the flag Q for the pulling up to it) W and repeat for as long as the escape is.

Summoner Skills:

Ghost is necessary to speed up and get to the lanes faster and get away in a bad situation.

With ignite you'll easily get runners, I've had so many people try to escape because Jarvan seems to bring their health down very low and of course while ulti is on CD and they try to escape, so IGNITE and you get your kill.

good alternatives:
Flash is a okay alternative for either, Ghost or Ignite. You can use flash for a lot of reasons, like to escape, But your flag Q combo will escape for a more efficient escape do that then flash.
Fortify is great for getting kills instead of Ignite as well. Stop them next to your tower with ulti and pop it to kill em quickly. Or just to defend your towers.
Clarity , Jarvan IV is very mana dependant so this can help a lot in replacement for either one.

Team work is a big part of playing Jarvan IV, He is based upon his team for success, Never should he be in a solo lane which is basically obvious. He will be useless with no team so please look this over to learn how he is BEST used.

Ultimate:

Jarvan IV's ultimate can easily turn a battle around in 2 ways, Either a good way for getting the kill and your excited etc. Or the bad way where you screw you and your team over, getting yourself caught with low health or a teammate which you could have saved will give the enemy a double kill or more. You can easily get your teammates killed with this ultimate which is not what we want!

So when using your ultimate take these into considerations:
1. Your teammates have full health or are backed away.
2. You have health the enemy does not
3. You have an escape plan if anything goes wrong.

If you just blindly use your ultimate you could help the enemy win.

Demacian Standard:

This skill is awesome for your team to become more powerful for one fight. Using this does damage to the enemy while also giving its passive to your team, This makes you able to have a fast attacking longer living team in a battle that could easily be won just because of this standard.

Be sure to use this when in a team battle to help your teams chances at winning by A LOT!

Play Video
All champ spotlights are a useful source of learning how to play a champion, So I always suggest watching them before playing.

I hope you all enjoyed this guide and used it to your advantage, If it did not help you at all I apoligize, and I hope I can fix it up some more to actually help.

REMEMBER: This guide is not complete and is still under construction, Therefore I am taking all feedback as to what should be changed or fixed, Also Voting down because you do not like something is considered trolling, If you don't like something don't vote till I have taken it into consideration and changed it.

I hope you enjoyed this guide, And I hope it helps you all out into playing Jarvan, I will be adding more info later on!