Ngl "Gravity" From Hazbin Hotel suits BEAST!CHUUYA/SOUKOKU so much.
Here's why:
GRAVITY SONG LYRICS AND HOW THEY FIT BEAST SOUKOKU↓↓
"The rage in me is terminal, there's no remedy but to burn them all". — When Chuuya went on a rampage after learning about Dazai's death.
"I still got a job to do, my mission's incomplete" — The "mission" could refer to Chuuya wanting to be the one to take Dazai's life someday but failed to do so since the latter had offed himself.
"Only a traitor could consider making peace" — This could be the moment when Atsushi went to visit him at the Government facility where he was chained up and when he ordered something to Atsushi but the latter told him that he no longer works for the Port Mafia.
"You think you're hell's great saviour, will you still when I return the favor?" — Could refer to Chuuya's desire to make the Armed Detective Agency pay for Dazai's "death".
"Wishing you were there when they needed you" — This fits cuz Dazai kept Chuuya at arm's length and Chuuya wasn't there to witness Dazai's final moment and not to mention there was something stated at the novel that says "The one I trusted as a partner and protected as a boss committed $uicid3 without telling me anything".
"The only soul who's ever completed you" — Get it? Because both Chuuya and Dazai were described as 'Two souls in One body' they both compliment one another and as the saying goes "Dazai makes Chuuya feel Human and Chuuya makes Dazai feel alive".
"Eye for an Eye says you owe me a debt" — Can be Chuuya referring to how Dazai owes him an explanation on why he offed himself without saying anything to him.
That's all ehehehe (◠‿・)—☆(ʃƪ＾3＾）
I love BEAST sm🥹🫶🏻