Akachilili

All you need is will! or something like that.

It's a basic purple does it all deck with all the greedy hacks. In the Thick of It let's you buy out three cards before triggering the Down the Rabbit Hole (I think). Then in DRT + 2xArcane Research + 2x Delve Too Deep gives you plus 6xp per mission, ideally, which let's you buy all the big spells you want.

Akachi has some of the best stats possible for a witch, along with a very solid special card and a trivial weakness. Spirit-Speaker lets you play all your good spell indefinitely, and sometimes makes Brand of Cthugha into 7 resources. It also let's as replay Living Ink undefinitely which gives us basically +2 in all stats for an action every 3 turns.

Other than that, we have Earthly Serenity and Deny Existence to not die from all the trauma we start the game with.

We're a little lacking in card draw and actions, but the actions we do pack a punch. And we could do with an additional arcane slot or two.