I think Cisco Ramon from the Flash is actually a witchwarper. He can open dimensional breaches to other Earths and travel in them. I think this class is beginning to grow on me, although we are playtesting the Vanguard this week. But I might be able to put together an NPC with a Witchwarper graft later on.
I haven't had a chance to playtest yet or see them in action, but I can't help but think of Elizabeth from Bioshock Infinite as well, especially in the portions of the game where she's helping you in combat.