Cassiopeia vs Locke

Land Noxious Blast (Q), then chain Twin Fang (E) while the poison lasts: the poisoned target takes extra damage, and you heal.

Hit a champion with Noxious Blast (Q) to kite: the spell gives you move speed, and Serpentine Grace (passive) makes every speed bonus more effective.

Place Miasma (W) on those trying to jump on you: inside the clouds, enemies are slowed and can't use movement abilities.

Cast Petrifying Gaze (R) toward those chasing you, after a Flash if needed: those facing you are stunned, the others only slowed.

Back instead of staying in lane at low health: Silver Stake (passive) adds damage to his autos that grows with your missing health.

Trade after Ashen Pursuit (E): it's his only instant movement, and its 10-second cooldown only resets if he gets a takedown.

During Soul Ignition (W), only hit him if you can kill him: at the end, he heals back part of the last damage taken, yours included.

Marked by Purgatory (R), stay above its threshold: if you have a heal or a shield, use it, because he seals marked enemies who drop below it.

If the Purgatory (R) artifact lands, hold the area where it fell: by picking it up, Locke raises his execute threshold for each sealed champion, for the rest of the game.