akutagawa died to save you in a very difficult fight, you were enemies, you 'hated' each other, but akutagawa sacrifice himself for atsushi, and atsushi every time is sad see the vision of akutagawa speaking to him, he misses him. no, akutagawa doesn't sacrificed himself because dazai ordered him to, and atsushi doesn't cries every night only out of guilt, maybe because he was really fond of akutagawa, they seem to always hated each other, like enemies, but that wasn't the reality