ok help pls

so theres this anime ive been searching for a while that prolly also has a manga but idk, i watched it like a year ago and i just CANNOT remember the name whatsoever.

my memories of the anime itself in general is extremely blurry but the only few things i can confidently remember is that:
- the protagonist ‘dies’ in the final episode
- theres a character called ‘doctor’ with blue hair
- theres an organization, its kinda like high card i think
-there were 12 or 24 episodes, it was a relatively short anime but wasnt surprisingly short
- the protagonist was one of those ppl with blonde hair with an uppercut or smth idfk what to call it