Hello i bought jarvan when he came out and he is super fun to play so i want to share what
i know about him to you let's begin

Jarvan works great with AD and DPS so you want to get as much as you can in masteries jarvan eraly game eats up a lot of mana so i go down utility to fix that and i get Awareness for leveling up faster

I bring this to chase and to kill champs easily use this if they are running away and own them
Again for chasing and for running away you know the drill

DON'T BRING THESE CAPS BECAUSE IT MEANS SOMETHING
Just dont
Not going to need it
Like i said before not going to need it
if your thinking of bring this just leave this page right now and look else were
mostly likeiy your never going to use it anyways
Nope.avi

You Can Also Bring
Nice for running away or chasing you can bring this instead of ghost
Nice for the mana just that though
Yep this is a good one to have bring it if you want to some more damage
If you want to gank or move your lazy *** to the tower bring this
To get of a bad situation cleanse is here for you

Martial Cadence
: Jarvan IV's first attack on his target deals 10% of the target's current health as bonus magic damage, this caps at 400 damage. This effect cannot occur on the same target for 6 seconds.
a nice passvie for that frist bow it can 400 damage a nice one to have
Dragon Strike
jarvan IV extends his lance through his opponent, dealing physical damage and then lowering their armor by a percentage for 3 seconds. If its lance contacts his standard it will pull Jarvan IV to its location, knocking up all enemies in his path.
really good skill you will lower there armor so your more damage and it dose some good damage
it self
Golden Aegis
Jarvan IV forges a shield protecting him from harm for 5 seconds and applying a 2 seconds slow to surrounding enemies upon activation. The shield adds more mitigation for every enemy champion nearby when activating.
this can really save you or get you the kill its really nice because it slows and gives you
a shield
Demacian Standard
(Passive): Grants Jarvan bonus attack speed and armor.
(Active): Jarvan IV throws a Demacian flag to a nearby area, dealing magic damage to enemies in the area and granting his passive benefits to nearby allies and again to himself for 8 seconds.
the passive is nice so you more AS and armor it dose good damage and to revels terrain
and buffs you and you and your allies you can combo it with Dragon Strike so it takes you the flag and knocks up and enemies you hit
Cataclysm
Jarvan IV heroically leaps to an enemy champion, dealing physical damage and creating a circle of impassable terrain around them for a 3.5 second duration. Jarvan IV can destroy the impassable terrain by activating this again. Champions can still leave or enter the area by using teleport abilities.
this is a good one it tarps you enemies and can do up to 500 damage to then and you trap then so you can own them it sucks that the can just used flash or use skills that can pass terrain
still this is a good skill

never build Warmog's Armor up first your waste you time getting hp and not getting AD and DPS
a doran shield and some pots are good for elaly game them buld up your boots and then start building up aFrozen Mallet this is good for its heath and its
damage and the slow is great also as of v1.0.0.118 Cloak and Dagger is a good way to get Tenacity without going Mercury's Treads also warbogs is good mid game if you want to tank

so you walk into top and you see ashe and sion there what to do well go for ashe have you lane
mate take sion and you go for ashe owning her and denying her of xp and gold and then if sion is not dead yet and you hp is not low go for him a

You got ganked it 1 vs 3 what do you do use your w and run into the jungle make turns until you get to a tower or you base or run into a lane with a team mates in it also if they catch up
use your summoner spells

you got a ninja guy around out to stop your killing strict what to do you buy orclas and try to bait him in to a trap and uitl him and own him

you got a team full of noobs (expet you) what to do well ya try to wait it out and do you best
it happens don't leave

PROS
great against carrys
can tank good
knock up
slow
shield
util is good for trapping
good scouting tool

CONS
eats mana up fast early game

v1.0.0.113
Golden Aegis' PVP.net description no longer states it triggers automatically

Dragon Strike
Cooldown increased to 10/9/8/7/6 from 9/8/7/6/5
Mana cost increased to 45/50/55/60/65 from 40/45/50/55/60
Golden Aegis shield strength reduced to 50/90/130/170/210 from 50/100/150/200/250
Cataclysm damage reduced to 200/325/450 from 200/350/500
Fixed a bug where Jarvan IV's banner caused a hitch the first time it was cast

some buffs and nerfs here