Welcome to my guild on how I build Yorick. I found this build seems to do best for me so far then others. I do not have any screen shots or uploads because I am still playing him more and more and working around items that are more depended on each and every game.

PRO

+ Nice pusher once mana isn't a problem.
+ Your ult is great to cast on the carry in a team fight.
+ Your W is great for chasing.
+ You do more base damage for every minion out.

Cons

- Well to start off early game hurts.
- Big mana problems if spamming skills early game.
- Minions die kinda fast.
- Slow farmer early on.
- Can be a little squishy.

- Is nice in a 5 man for mobility and laning but I wouldn't recommend it in a 3.
- Great for a early start and getting that kill. As well as 1v1 late game.
- Great for chasing down with your W as well as ganking.
- Great for those who aren't satisfied with Flash.
- Very helpful. Weather it's to get close for the kill or to get out fast.

Unholy Covenant(Passive)
*Yorick's basic attacks deal 5% more damage for each summon that is active. Meanwhile, Yorick's Ghouls have 30% of Yorick's Attacks Damange and Health*

This passives comes in great handy late game because you will be spamming minions all day errday and gives more damage for more minions that are out.
Omen of War(Q)
*Yorick's next attack will deal 30/60/90/120/150 (+?) physical damage and summons a Spectral Ghoul for up to 5 seconds. The Spectral Ghoul deals 8/16/24/32/40 (+?AD%) 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*

This spell is great to not only hit hard but to chase after somone after using your W or just to get that last hit. I don't max this early on at all because of how easily harassed Yorick is. You won't have enough time to spam this on minions or champions. It comes in handy later game in my opinion.
Omen of Pestilence(W)
*Yorick summins a Decaying Ghoul that arrives with a violent explosion dealing 60/95/130/165/200(+?AD%) 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. Cost: 50/55/60/65/70*

This is where it's at! This is what you will be able to Harass/push lanes/and engage with. Once maxed you will be able to spam this in lane and push nicely aswell as doing nice damage.
Omen of Famine(E)
*Yorick deals 55/85/115/145/175 (+?AD%) magic damage and heals for up to 50% of the damage dealt. A Ravenous Ghoul is summoned behind his target, which heals Yorick for the damage it deals and lasts for up to 5 seconds*

I find this better to level up then your Q. Reason being is that along with W you will be able to harass quite nicely aswell as healing for health. I level this to 3 and leave it there because the health gained at 3 should keep you healthy in lane.
Omen of Death(R)
*Yorick conjures a revenant is the image of a target allied champion. Revenants deal 50%/75%/100% of the target ally's Attack Damage. If his ally dies while the revenant is alive, the revenant sacrifices itself to reanimate them. Revenants and reanimated allies lose 10% of their maximum Health per second*

This is very nice. When casted it creates a reanimation of the target you use it on. The Reanimation will only last 10 seconds. I find it best to cast this on the carry as soon as the team fight initiates.

Start with regrowth pendant and a health pot. Max your W and E first because you can't get into melee range to last hit very well.
Port back to grab a philosophers stone and boots at 715 gp.
Port back again at 995 GP for a tear. Congratulations, you now have enough mana regen to use Yorick. If you maxed W first, then E, you can actually farm in your lane now.
Once you have a manamune you can do some nice damage and spam spells much more without to many mana problems.
These boots work nicely with Yorick. It will allow you to use you W and E a hell of alot more and build your Manamune up. The CDR is nice too.
This will give you health the one thing Yorick might need most. Yorick doesn't have the greatest health and this will allow you to get in a team fight and not drop so fast.
This is great for being tanky as well as doing more damage because of the 2% max health becoming attack damage.
If now your doing great in lane the Trinity Force will increase damage quite nicely and help you chase/win more. *The last 2 items are situational*
If you need the extra magic resist or health the Banshees veil might be better over the Trinity Force depending on the fight. *The last 2 items are situational*

For runes I see it this.

Marks - Armor pen is nice for the dps because your W and E are scaled on Attack and the armor pen will allow those and basic attacks to penetrate armor also saving you money so you don't need to buy armor pen items.

Seal - Flat armor. It will come in great handy early game for laning as well as late game. Doesn't hurt to have the armor.

Glyph - Flat magic resist. Same as armor it is needed just as much. You can replace these with
mana if you want but I really prefer the MR.

Quint - More armor pen! All day every day.

0/9/21

These are fantastic for mana/health regen. The flash is needed for sure. Yorick isn't the greatest farmer so the gold per 10 is great. Clean and simple caster build with the extra defense.