Senna vs Nautilus

Attack the souls held by the Mist whenever you can: each soul freed with Absolution (passive) increases your AD, attack range and crit chance.

Fire Piercing Darkness (Q) through an ally or an enemy to hit both: the beam heals your allies, and damages and slows enemies in the line.

Cast Last Embrace (W) on a target that's already slowed or immobilized: after a short delay, they and nearby enemies are rooted.

Cast Curse of the Black Mist (E) to engage or escape with your team: allies who enter it are camouflaged, then fast and unselectable.

Cast Dawning Shadow (R) to save an ally across the map: the beam has unlimited range and shields allies.

Once he hits level 2, stay behind your minions: the Dredge Line (Q) anchor hooks the first enemy hit, then the Staggering Blow (passive) auto keeps you in place.

When he casts Riptide (E) near you, stay put until it ends: its three explosions spread out around him, and running too early makes you take the next ones and their slow.

When Dredge Line (Q) misses you, keep your distance: it's his only spell to reach you, on a 14 to 10 second cooldown.

When he aims Depth Charge (R) at an ally, don't stand between them: the shockwave chases its target, and every enemy in its path takes a knock-up.