Yone vs Mordekaiser

Hit twice with Mortal Steel (Q), minions included, to charge the next one: it makes you dash forward and knocks the enemies hit into the air.

Cast Spirit Cleave (W) on several champions at once: it deals damage based on their max health, and your shield grows with the number of champions hit.

Cast Soul Unbound (E) to engage: when it ends, you snap back to the body you left behind, and part of the damage you dealt to champions is repeated.

Cast Fate Sealed (R) through several enemies: everyone in the line is hit and knocked into the air toward you, and you reappear behind the last champion hit.

Stay near your minions against Obliterate (Q): its damage increases when it hits only one enemy.

Dodge Death's Grasp (E): it pulls you toward him, into his other spells, and it has a 16 to 8 second cooldown.

If you have range, kite him: Mordekaiser has no dash, and only Death's Grasp (E), which pulls you in, closes the distance.

In Realm of Death (R), save your mobility spells to escape him rather than for the duel: he steals part of your stats, and keeps them if he kills you.