Hello, and welcome to my Yorick guide!
This is my first guide, and i will show you the way i play Yorick, The Gravedigger. Yorick is a champion who is often underestenimated but can do surprising amounts of damage early to lategame, if you build him right.
I belive that there is no one way to build any champion, your items, masteries and summoner spells may vary from game to game depending on your team setup, enemys etc, but this might help you to find the build and playstyle that suits you :)

Please read the whole guide, try it out in a game or two and post a comment to why you didn't like the guide before you downvote. All constructive criticism is welcome, and i'm open to suggestions.

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

2011/7/23 - Build not created yet

Pros

- Good farmer with your ghouls
- Very good harasser with [Omen of Pestilence] and [Omen of Famine]
- Strong damage
- Good pusher
- Decent ganks with Omen of Pestilence
- Extremly hard to kill in 1vs1 fights

Cons

- Squishy earlygame
- Mana problems early-mid game
- Ghouls sometimes does nothing for a few seconds, wasting precious damage
- You can't control the ghouls
- Ghouls die very fast
- No inbuilt escape mechanism, only the slow from Omen of Pestilence

Unholy Covenant - Passive

Yorick's summoned ghouls deal 35% of Yorick’s attack damage and have 35% of his total health. The Ghoul's health is reduced by 20% of their max health every second. In addition, Yorick takes 5% less damage and his attacks deal 5% more damage for each summon that is active.

This is what makes Yorick what he is. Your ghouls will be able to do surprising amounts of damage, and you will too thanks to the 20 % bonus damage.


Omen of War - Q

Yorick's next attack will deal 30 / 60 / 90 / 120 / 150 bonus physical damage and summon a Spectral Ghoul.


The Spectral Ghoul deals 8 / 16 / 24 / 32 / 40 physical damage and moves faster than the rest of the ghouls. While the ghoul is active, Yorick moves 15 / 20 / 25 / 30 / 35% faster as well.

This is what makes Yorick a prime candidate for Trinity Force. When you use it, you reset your autoattack timer and your next attack hits harder, and summons a hard-hitting ghoul. Very useful, combined with Trinity Force you will deal lots of damage with this skill.
I get this skill at level 3, to increase my burst damage and to get another ghoul. It is maxed second, mostly for the improved movement speed for chasing, and the ghouls bonus damage.


Omen of Pestilence - W

Yorick summons a Decaying Ghoul that arrives with a violent explosion, dealing 60 / 95 / 130 / 165 / 200 (+0.8 per bonus attack damage) 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%.

This skill is extremly useful for a lot of things. It doesn't need a target, so you can use it to check bushes for enemys, and for popping Shacos Jack In The Box and Teemos Noxious Trap. It is also good for chasing by using it on the enemy, and escaping by using it towards the chaser, preferably on him. Remember that the ghoul also slows everyone around him, and not only when you cast the spell. Using this spell at the right moment can let you kill enemys who would've escaped otherwise, or save your life when you could've died.
Since this is the skill with most damage level 1, and since you can check bushes with it, i pick this skill first, but i max it last due to that i feel other skills is more useful at higher ranks.


Omen of Famine - E

Yorick deals 55 / 85 / 115 / 145 / 175 (+1.0 per bonus attack damage) 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.

I take this skill at level 2, and max it first. The heal you get from this skill gives you extremly strong staying power in lane. you can basically stay forever, if you got enough mana. It is also very good harassment combined with your Omen of Pestilence.


Omen of Death - R

Yorick conjures a revenant in the image of one of his allies that will has 50 / 75 / 100% of their max health and attack damage. If his ally dies while its revenant is alive, the revenant sacrifices itself to reanimate them temporarily by restoring them to full health and give them time to enact vengeance.

With this skill, you can quickly turn a 1vs1 to a 2vs1, and the killing power this gives you lategame is not to be underestenimated, even though it can be pretty weak early in the game since it's only 50 % AD then. Use it on the one with most AD in your team, to squeze

For summoner spells, i usually pick

Flash is an overall versatile spell, useful on any champion, for teleporting over walls to escape, gank, chase, or just to close distance between you and your enemy.

and

exhaust can turn the tides of a fight in your favor, by crippling their damage, and together with your Omen of pestiliance bringing a very powerful slow, making them almost unable to escape you. Good for escaping, chasing, and winning fights.


Those are the spells i belive is most useful for Yorick, but it's mostly personal preference.

Other viable options include:

If you don't like flash, or if you are used to this spell, it is certainly a good choice. You can get to lanes faster, chase fleeing enemys, or make your escape with this spell.

If you feel you want more burst earlygame, or if you want to shut down that Dr. Mundo/ Vladimir/ Warwick, this is the spell for you! Some extra damage and a nasty 50 % healing reduction can be very useful, but i personally feel that i don't need it.

A great spell, might save your life and get you some kills by removing that Teemos blind dart, cleanse away the Luxs snare, or just getting rid of a dangerous slow after flashing.

What you shouldn't take:

You will probably have some mana problems, but since you're only a few seconds from your base, clarity isn't as effective here as in Summoners Rift.

It might be useful, but you aren't the jungler.

It is a small map, you can get to your lane fast. No need to waste a summoner spell on that.

While this might be useful, you got your Omen of Famine for health :)

A very useful spell, but it's better if you let a support take this.

Not a bad spell, but chances are big it won't even manage to save your towers if you are dead and enemys is pushing, it will only delay death a few seconds.

Just simply not worth it.

A good spell with awesome speed boost, untill you think of the 9 minute cooldown...

For runes, i pick:

Greater Mark of Desolation Greater Mark of Desolation x9. Since even if your Omen of Pestilence and Omen of Famine do magic damage, Around 60-75 % of your damage will still be physical. These will help you improve your damage.

Greater Seal of Clarity x9. Because you are mana hungry through the whole game. these will help you with that problem.

Greater Glyph of Focus x9. With these and my recommended masteries, you will enter the game with almost 15 % Cooldown Reduction, and you want as much of it as possible so you can spam your ghouls more.

Greater Quintessence of Desolation Greater Quintessence of Desolation x3. Since even if your Omen of Pestilence and Omen of Famine do magic damage, Around 60-75 % of your damage will still be physical. These will help you improve your damage even further than the marks alone can.

Other good choices:

Greater Mark of Strength x9. Since all your spells scale on AD, these will help you do more raw damage against targets. But without armor penetration, you might end up doing less damage with these than with the Greater Mark of Desolation.

Greater Seal of Replenishment Seal of Replenishment x9. If you want that bonus regen early in the game. just remember, that the Greater Seal of Scaling Mana Regeneration gets better than these at level 7.

Seal of Resilience x9. These seals will give you 13 more armor to play with through the game. I don't feel they are needed though, with you getting Frozen Heart rather early.

Greater Glyph of Shielding x9. These runes will more than double your already high MR/Level, and will give you some nice protection against casters. I prefer the MR/Level before the flat MR, since the MR/level is better at level 9 or above, which is reached fairly quickly. and casters isn't that dangerous earlygame.

Glyph of Celerity x9. If you really, really want that 2,25 more CDR at level 18, pick these. the problem is, you'll still need a buff/elexir/item to reach 40 %, so it's really not much difference about the flat and per level ones, except that the per level is only as effective as the flat ones at level 13, and the difference isn't going to be big even at level 18.

Greater Quintessence of Strength x3. Since all your spells scale on AD, these will help you do even more raw damage against targets that the marks alone would. But without armor penetration, you might end up doing less damage with these than with the Greater Quintessence of Desolation.

Greater Quintessence of Fortitude x3 These will make you even more bulky earlygame by giving you an aditional 76 health. I recommend you to get these if you are planning not to start with Dorans Blade to still make you bulky earlygame.