Seraphine vs Swain

Make Surround Sound (W) your third basic spell: Stage Presence (passive) casts it twice, and the second, cast while shielded, heals your allies.

Cast Beat Drop (E) on enemies that are already slowed: they're rooted, and those already immobilized are stunned.

Save High Note (Q) for a wounded target: its damage grows with the health they've lost.

Cast Encore (R) through an ally toward the enemies: each champion hit, allies included, extends the spell's range.

Get out of the Nevermove (E) path as it comes back: it only roots on its return to Swain, then he can pull each rooted champion to him.

Leave the area as soon as Vision of Empire (W) appears: it strikes and slows 1.5 seconds later, and each champion hit gives him a Soul Fragment.

During Demonic Ascension (R), back off and hit from range if you can: he only drains nearby enemies, and his form ends when he stops draining.

If you have Grievous Wounds, apply it during Demonic Ascension (R): the drain heals him every second, and that healing keeps him alive.