Finnian: Finnian has forgotten his time with the doctors/the experiments and the night that he escaped from the lab. So there will likely be doctors in lab coats and syringes running around as well as other children shaved baled with the back of their neck marked. Finnian will need to confront and accept his identity as Subject 12, both for his abnormal strength, the inability to save the other patients and the lives he took escaping; all tied to the memory which he has forgotten.

Seimei: Seimei has had no memories lost, but will be glad to poke around in other's minds.

Undertaker:: Also no losing any memories but will certainly meddle in others, and possibly try to view a few of the cinematic records of those who have 'lost' memories.