The Birthday Massacre-One
https://www.youtube.com/watch?v=zyYcS5kidhw
I get the feeling of a solitary figure that may be dealing with a past of some sort. Some anime's that popped in my mind is Chrome Shelled Regios, Planetarian, Gargantia on the Verdurous Planet, Swordart Online, or Dancing with Dragons. Perhaps it could relate to an individual that may not be a main character in another anime. Come to think of it there are alot of those
