What boss theme from the Souls series (excluding Bloodborne) would 你 give to the (ex)villains of the show? These are for those that deserve such a theme for what they have done in the past.

To me, here's how it would be:

Nightmare Moon: Moonlight 蝴蝶 (Dark Souls I)
Discord: Bell/Belfry Gargoyles (Dark Souls I & II)
Trixie: Iudex Gundyr (Dark Souls III)
The Flim Flam Bros.: Vanguard (Demon's Souls)
皇后乐队 Chrysalis: Fool's Idol (Demon's Souls)
King Sombra: Vordt of the Boreal Valley (Dark Souls III)
Sunset Shimmer: Flamelurker (Demon's Souls)
Lord Tirek: Yhorm the Giant (Dark Souls III)
Starlight Glimmer: Abyss Watchers (Dark Souls III)