Y/n is one of the strongest people which lives with the avengers, s/he's a vampire, has to eat organs and drink blood to survive, but s/he's with the avengers, everyone trusts her/him. One day a person hits her/him with his power not on purpose, the power of the person makes the person he touches go back (with the mind) when the person had the half of the actual ages (example: a person is 50yrs old and with that power the mind of the person goes to the past when he was 25 years old even if the body is still the same). Y/n is also very old, s/he's probably about 1000 years old, her/his mind will be of when s/he was 500 years old for an entire day...