The seven's witch (TS Harem x Futa caster reader)

After caster was killed in the 5th holy grail war her master used all of his command seals to give one order, to live a happy life, and that was order was heard by a certain vampire and he granted that masters dyeing wish out of pure entertainment, so before she died he send caster to a world where magic is a little different then the magic here and to make this more entertaining he gave her a command seals, a relic, and a grimoire with the spirit of a counter guardian but ones thing is for shure (Y/N) Medea is going to have one hell of a life.