Whatever, I'll Just Go Crazy [Western Crossover]

I hadn't even finished writing the Conan part, and now the canon's gone off the rails. I'll leave it bald for now and rewrite the setting later. A memory-lost, terminally ill Qian Mu arrives in another world. He still has some hazy memories, but his British butler doesn't agree with his wild guesses. [You're currently Black Mask, but you're not really Black Mask. You just took his place. Your real identity is actually, ] "I know, Alfred. I'm Batman." He's got a secret identity and a retired British agent for a butler. How could he not be Batman? One day, while Qian Mu is dreaming up his revenge plan, a muscular guy in a red helmet drops from the sky, lands on his lap with a gun, and threatens him menacingly Half a minute later, Red Hood is screaming in terror, "Don't you fucking die!" He spends the whole night piecing Qian Mu back into human shape before rushing him to the ICU. After being discharged, Qian Mu finally realizes that he isn't in Detective Comics, but in Case Closed. Still, he really is the leader of a criminal organization, and his life's goals are to save himself from his terminal illness and rescue his classmates, who are partners in justice. [One of your classmates has a secret identity and spends all his time lurking in the darkness.] So his classmate is Batman! After much soul-searching, Qian Mu kidnaps the famous villain Joker that very day, instantly claiming the top spot on Gotham's crime-boss list. Everyone in Gotham knows that during his debut, Qian Mu laughed maniacally as he proclaimed his evil scheme: "It's all so Batman and I will go to bed early and wake up early!" Batman, champion of healthy sleep habits: "?" [You're always disappearing without a trace. The organization only survives because someone else is carrying the burden for you. He's hot-tempered, hates betrayal, and is good with a gun.] Such a capable subordinate must be promoted immediately! Red Hood, who just got promoted in a second: "?" [You also have a nemesis, a seventeen-year-old high school detective. His deductive skills are slightly inferior to his father's, and even when his body gets smaller, his mind remains sharp.] Red Robin, who suddenly turned into an elementary school student: "?" [An undercover cop infiltrated your organization. He wants to steal your people from under your nose, and take you with him while he's at it.] Nightwing, who cautiously infiltrated the organization planning to work from within with Red Hood: "?" Qian Mu coldly kicked Nightwing out of the organization, then turned back to face off against Batman on the rooftop of Wayne Tower. "All right, Batman, there's just one last round of mahjong. If you lose, your beloved Joker will be chopped into pieces, disinfected, and flushed down the sewer. You'll never find him!" Batman: "...All one suit. I win." He gathered the tiles and went home, then went to bed happily at ten. Gotham was peaceful once again. In the middle of the night. Batman appeared by the window, looking grim. "Are you really terminally ill?" Qian Mu jolted awake and shouted angrily, "Why aren't you asleep yet?" Wait, he really is terminally ill. Where's his medicine?! The protagonist is a max-level character from the Case Closed world who wandered into this one. The story plays with mistaken identity and self-perception. Just like the title suggests, his mental state is extremely beautiful. You don't need to read the previous story to follow this one. It's almost entirely DC, with only a few Case Closed characters making cameo appearances. There won't be any Case Closed or other anime storylines mixed in. Premise: Dreams can always come true.