Sion vs Yone

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.

Get out of his line after two Mortal Steel (Q) hits: the next one makes him dash forward and knocks the enemies hit into the air.

During Soul Unbound (E), avoid taking hits: when he snaps back, part of all the damage he dealt you is repeated.

If you have ground-targeted CC, place it on the body he left behind: when Soul Unbound (E) ends, he has to return there.

Judge his threat by his crit items more than his level: Way of the Hunter (passive) raises his critical strike chance, so each crit item does more for him.

In teamfights, don't line up with your allies in front of him: Fate Sealed (R) hits every enemy in a line and knocks them into the air toward him.