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Passive - Whenever a minion ( friendly or not ) dies near Yorick, they become a Ghoul. He can have up to X of them, and gains damage reduction and movement speed for each Ghoul alive. Ghouls last 1 minute, attack nearby enemies ( but don't prioritize champions ), have their stats based on Yorick's, ignore unit collision, quickly lose health when attacking turrets and interect with his other abilities.
Q - Upon death, Ghouls heal Yorick. Activating the ability damages enemies in a cone in front of Yorick and creates a short-lived Ghoul for each champion hit, while also briefly slowing them.
W - Yorick sacrifices some of his Ghouls to surround the target. If it's an ally ( or Yorick himself ), the Ghouls will give them movement speed and block enemy projectiles until they get killed. If it's an enemy, they get slowed and get attacked by other Ghouls. When the effects end, all remaining Ghouls die.
E - Yorick commands some of his Ghouls to rush to the target location, damaging all enemies along their way. If they hit a champion, they die, the target gets slowed and damaged. Yorick heals himself for a portion of the damage dealt.
Note: It's a skillshot similar to Heimer's W.
R - Yorick sacrifices some of his Ghouls to create an area of Undeath around him. Upon taking fatal damage, any champion within the zone gets revived for a few seconds and becomes a Suplicant. Suplicants lose their health quickly and move slightly slower, get permanently revived if they kill another champion OR Suplicant and die after 2.5 if they get outside the zone. When the effect ends, all champions gain increased movement speed.
Note: Yorick cannot create Ghouls while the zone is active.