Victorie, Spirit of Awakening. Costs 100 DC per, used to Awaken every single unit.

Best to buy Chydis or two (for first guaranteed CR and SU) and then hoard up at least 400 for the unlikely event of devs deciding to rotate the Trading Post contents again (don't hold breath for that on, it took them what, two years to do the current rotation )
If DCs happen to pile up too high, buy Saki. She's pretty good at what Ninjas do, and with SAW can clear waves pretty good. And, as an added bonus, she's a good outlet to burn the Black spirits