Senna vs Rell

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.

Back off as soon as she speeds up toward you: Full Tilt (E) doubles her move speed toward enemies, and her next auto explodes.

Don't count on a shield against her: Shattering Strike (Q) breaks all shields and stuns every unit in its line.

Spread out from your allies when she gets into melee range: Magnet Storm (R) violently pulls nearby enemies in, then keeps dragging them toward her.

Move away from her once she's on foot: after Ferromancy: Crash Down (W), she's slowed, but gains armor and magic resist.