Passive: Unholy Covenant
Yorick's basic attacks deal 5% more damage and Yorick takes 5% reduced damage for each summon that is active. Meanwhile, Yorick's ghouls have 35% of Yorick's Attack Damage and Health.
This coupled with defensive masteries and some defensive items make Yorick extremely tough when fully engaging in fight with all of his ghouls out.
Q: Omen of War
Yorick's next attack will deal 30/35/40/45/50 (+120% of attack damage) physical damage and summon a Spectral Ghoul for up to 5 seconds.
The Spectral Ghoul deals 8/16/24/32/40 additional damage per hit and moves 15/20/25/30/35% faster. While the ghoul is active, Yorick moves 15/20/25/30/35% faster as well.
Cooldown 9/8/7/6/5 seconds
Cost 40 mana
This skill gets maxed last simply because
Omen of Pestilence and
Omen of Famine are your main harassment skills, and this requires melee range. Any skill that empowers an autoattack synergizes nicely with
Trinity Force, and I find that one level of this plus the
Sheen active is enough of a whack until late game. That said, this is a nice skill to keep hounding your opponent, given the speed buff you get coupled with
Omen of Pestilence's slow and
Trinity Force's movement speed and slow.
W: Omen of Pestilence
Yorick summons a Decaying Ghoul that arrives with a violent explosion, dealing 60/95/130/165/200 (+100% of ability power) magic damage and slowing nearby enemies by 20/25/30/35/40% for 1.5 seconds. While the Decaying Ghoul remains alive, nearby enemies continue to be slowed by 10/12.5/15/17.5/20% for up to 5 seconds.
Cooldown 12 seconds
Cost 40/45/50/55/60 mana
This skill is great for harassment along with
Omen of Famine, and usually starts your chase once you land the slow on your opponent. As an AoE, it also helps quickly push your lane. This skill has slightly better damage scaling, and lower mana costs, than
Omen of Famine. So, if all else is equal, I will tend to max this before
Omen of Famine. But, it will still depend on whether the sustain or slow will be more useful at the moment.
E: Omen of Famine
Yorick deals 55/85/115/145/175 (+100% of attack damage) magic damage and heals for up to 40% of the damage dealt. A Ravenous Ghoul is summoned behind his target, which heals Yorick for the damage it deals and lasts up to 5 seconds.
Cooldown 10/9/8/7/6 seconds
Cost 55/60/65/70/75 mana
This is your other harassment skill, as well as your sustain skill. It has lower cooldown and higher mana cost than
Omen of Pestilence, so be careful you don't run yourself out of mana before you need to commit to a fight. However, in a fight, spam this sucker every time it comes off of cooldown.
R: Omen of Death
Yorick conjures a revenant in the image of a target allied champion. Revenants deal 45/60/75% of target ally's Attack Damage. If his ally dies while its revenant is alive, the revenant sacrifices itself to reanimate them.
Cooldown 120/105/90 seconds
Cost 100 mana
This skill is similar in ways to both Zilean's
Chrono Shift and Mordekaiser's
Children of the Grave. It can be used to "save" a dying ally, except that the person is still dead, but can keep on fighting. It can also be used to create an extra champion for a fight. I like to use it on either myself or a high attack damage character early in a fight rather than use it for a last minute save. Having the extra damage in a fight often means we can kill enemies without people dying. And, even if you do use it to "save" someone, it's only extending the fight for them instead of compounding damage in a shorter amount of time, if that makes any sense. The exception to this is when you use it on an AP champion. In that case, it is better used just before they die so they can live on and keep using abilities. Having a revenant of an AP champion while they are still alive doesn't help much, since their auto-attack damage is so low. Another thing to note is that often people don't realize they have died and try to back away from a fight instead of going nuts on the enemies. So, it's obviously most effective if you can communicate over a voice chat program, or if you just use it on yourself.
This skill is a great tool for defending a point against one or more enemies. It is also very useful in harassing and keeping enemies away while you are capturing a point. You can still control the revenant while channeling the capture using the pet control keys (i.e. Alt + mouse clicks by default, I believe). So, use that to your advantage. Actually, if you right-click on a point to capture it, your revenant will often just walk up next to the tower and stand there doing nothing unless you use the pet controls. So, you definitely want to learn how to do that effectively.