Sion vs Yorick

Last-hit minions and monsters for Soul Furnace (W): each kill permanently gives you max health, more on champions, large minions and large monsters.

Slow your target with Roar of the Slayer (E) before charging Decimating Smash (Q): they're less likely to get out of the area.

Charge Decimating Smash (Q) for at least 1 second: below that, the hit only slows, and beyond it, the knock-up and stun last longer the more you charge.

After you die, hit the nearest champion: during Glory in Death (passive), your autos are much faster, heal you and deal damage based on their max health.

Cast Unstoppable Onslaught (R) from far away to engage or roam: unstoppable for 8 seconds, you stun longer and hit harder after a long charge.

Dodge Mourning Mist (E): once marked, you lose armor, his nearby graves keep raising Mist Walkers, and his units rush toward you.

Kill his Mist Walkers, summoned by Shepherd of Souls (passive), before going for him: a single auto or single-target spell is enough for each.

If Dark Procession (W) traps you, hit the wall to break it instead of waiting for it to disappear.

If you can, take down the Maiden of the Mist before Yorick: summoned by Eulogy of the Isles (R), she carries a large part of his damage and push.

Don't let him split push alone: with the Eulogy of the Isles (R) Maiden and his Mist Walkers, he quickly threatens a tower. Send someone to answer him.