Galio vs Swain

Engage with Justice Punch (E), release Shield of Durand (W), then place Winds of War (Q) during the taunt: the tornado deals damage based on max health.

Against a magic-damage opponent, don't take free hits before a trade: after a few seconds without taking damage, Shield of Durand (W) gives you a magic shield.

Charge Shield of Durand (W) before releasing it, after a Flash if needed: a longer charge means a longer taunt, more damage and a wider area.

Watch the map and join fights with Hero's Entrance (R): your allies in the area get a magic shield, and your landing knocks enemies into the air.

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.