The work of gravediggers is essential amongst the living, but invaluable in the Shadow Isles. There are many shades of death there, and each is embraced rather than feared or reviled. One can only ascend from one state to the next with the magical aid of a skilled professional. At the end of the first Rune War, Yorick Mori made his living as a gravedigger. His family owned and maintained the Final Rest Memorial, one of the oldest cemeteries in Valoran. The shovel he employed for his work had been passed down for generations. Each gravedigger taught his son that this shovel was imbued with the spirit of every forefather, and that those spirits would protect him during the long lonely nights amongst the tombstones. To his eternal regret, Yorick died without an heir, bringing the proud Mori line to a close. His body was interred with his shovel in the family mausoleum, and the Final Rest Memorial soon fell to ruin. Death, however, was not the end Yorick had expected.
Yorick emerged on the haunted shores of the Shadow Isles – not quite dead, definitely not alive – still clutching his beloved shovel. He soon learned that with it he could act as a ferryman for the Isles' undead denizens, helping them climb death's many-tiered ladder. This proved a curse, as a gravedigger must "bury his quota" before he too can ascend, or so the legend goes. No one knows what "his quota" is. Yorick dug tirelessly, waiting in vain for the day when he would be freed of his burden. As decades turned to centuries, the shame of his failures came to a head. He returned to Valoran to find his corpse, convinced that salvation might be buried with it. When he arrived, no trace remained of either the mausoleum or the memorial. Hope nearly lost, he discovered the League of Legends, and there saw an opportunity to immortalize the family name he allowed to be forgotten ages ago.
"Die first, then we’ll talk." -- Yorick
Passive-Unholy Covenant: Yorick's attacks deal 5% more damage for each summon that is active. Meanwhile, Yorick's ghouls deal 30% of Yorick’s attack damage and have 30% of his total health.
This is why you need blue buff. You will notice this build has nothing for your mana, this is because you need blue buff all game long. You need to spam your spells like crazy in fights. Not only do you personally hit harder but your ghosts are hitting too.
Omen of War: Yorick's next attack will deal bonus physical damage and summon a Spectral Ghoul that deals additional damage and moves faster than Yorick's other ghouls. While the Spectral Ghoul is alive, Yorick moves faster as well.
This is your bread and butter all game long. You want to max it first because it does great damage and the mana cost doesn't increase. This is how you will initiate most fights.
Omen of Pestilence: Yorick summons a Decaying Ghoul that arrives with a violent explosion, dealing damage and slowing nearby enemies for 1.5 second. While the Decaying Ghoul remains alive, nearby enemies continue to be slowed.
If you choose to lane Yorick this will be your harrassing and farming spell. Because this is a jungle build we max it last. Still spam it for the extra damage.
Omen of Pestilence: Yorick steals life from his target and summons a Ravenous Ghoul that heals Yorick for the damage it deals.
This lets you jungle easier, finish off champs, and stay alive longer. It is a great spell but doesn't do too much until you get your atmas.
Omen of Death: Yorick conjures a revenant in the image of one of his allies. If his ally dies while its revenant is alive, the revenant sacrifices itself to reanimate them and give them time to enact vengeance.
This is your ultimate. It is interesting. It is like a cross between Mordekaiser, Shaco, and Zileans ult. The way I actually use it the most is to ensure a kill or to lay down more dsmage by ulting your AD carry at the beginning of a team fight.
Pros / Cons
Easy Jungler after first pass
Not a great farmer
Can be difficult to explain why you are in the jungle so much
Weird ganks that are difficult to get used to
Creeping / Jungling
Basically you can start wherever you want. But unless you have health quints you can't start at blue without a leash.
So if you get a leash, start at blue and move your way through your own jungle. Skip red and take double golems. Then blue pill. Come back for Lizard. Then grab Wraiths and dogs and then head out for ganks.
Keep clearing your jungle and the enemies all game. No really, all game. You don't farm terribly well so you need to clear it constantly.
Take dragon once you have Wriggles.
When Jungling your Q resets your attack timer, so you want to autoattack, then Q. This will be basically a super triple attack.
Okay, this is a little weird. Your ganks are basically a quick pass through. You lack hard CC so sometimes you will have your laners initiate and ult the one who autoattacks harder and spam your spells and leave. This is often enough to score your laners a kill or two.
There is no waiting patiently in bushes for yorick. He gains nothing from the opportune moment. Your laners should engage and you should jump in on your way.
The other kind of gank is literally ulting your teammate when they are close to death and continuing to run. This puts the opposing laners on edge and lets your team put out extra damage.
Style of Game
You will find that with this build you do poorly in team fight heavy games. In general the longer the laning phase lasts the better you will do. So emphasize this to your team. Tell them to last hit only for as long as they can. The reason behind this is you rely in a high creep score to get your items.
Yorick, unfortunately, is about as good of a farmer as poppy. So when you have games where the entire team is pushing mid all the time at 16 minutes you will be unable to clear the jungle.
While you do great in team fights it will be better if they are only occasionally because of said farming issues. Teamfights gimp your gold intake because you will only pick up kills if you are deliberate in doing so. If you take the kills you starve your carries.
1v1 is really the shining spot of Yorick. You can spam your abilities with your ult on which gives you insane 1v1 DPS with solid survivability. So roam a bit when the jungle is empty and keep wards up.
Trinity or Frozen Mallet
Basically I choose Frozen Mallet for the extra surviavbility, it's synergy with Atma's, and the 100% chance to slow. I find that reliable CC(even soft CC is useful on Yorick).
That is not to say that trinity isn't a great item. Trinity gives you a lot better damage output, so if you aren't the only tanky champion grab trinity. You will do more damage but won't last as long in fights.
It really is just personal preference.
Jungle Yorick is an off tank with some great utility, he is a ton of fun to play and terribly difficult to kill. Be aggresive when you can and invade their jungle like it is your own and you will do fine.