Senna vs Nami

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.

Change direction when she casts Aqua Prison (Q), then step up if she misses: it's her only stun outside her ult, on a 12 to 8 second cooldown.

Avoid trading when she casts Tidecaller's Blessing (E) on her ally: their next autos and abilities slow you and deal more damage.

Step out to the side of Tidal Wave (R): it travels a long way but moves slowly, and its slow lasts longer the more distance it has covered.

If you can engage, target Nami when she steps up: with no dash or leap, she can only walk away.