The Lady of (New) Avalon

Sirius follows up on trying to get Snape expelled (or killed) with getting a sex change. Incidentally realises Bella doesn't hate her, is drawn back into the Family and the Dark. Attempts to end the war through diplomacy, accidentally escalates it. Is very conflicted about everything. AU First War, fem!Sirius (Aster), dark!Lily, worldbuilding from Coming of Age and The Plan series.