[Western Crossover] The Joker Says He's My Brother

[Main Story Complete, Extra Chapters Updating] After I lost my memory, my brother took care of me the whole time. Even when I kept hearing the laughter of clown-like creatures in my ears, he never abandoned me. So I always did what he told me. He told me to go to Arkham for treatment, so I went. He told me to go find some fun, so I did. He told me to earn the Bat's trust and then stab him in the back. I... Something about this seems a little off, doesn't it? But for my brother, I did it anyway. I found the Dark Knight, worked hard to earn his trust, and resolved to betray him at the crucial moment and run into my brother's arms. I always thought my brother was Gotham's greatest villain, the Dark Knight's eternal enemy, and the Joker's... counterpart. Until one day, my brother smiled and told me, "Dear little sister, they usually call me the Batman Who Laughs." Me, finally realizing that he had been setting himself up all along: "..." So I'm actually Gotham's biggest clown?! To keep myself from becoming Gotham's biggest clown, I decided to get revenge on my brother... Using the very method he taught me :-D I'd take advantage of his trust, betray him at the crucial moment, and run into the Bat's arms. Then I'd ask him, "Why aren't you laughing, big brother?" [Updates at 9 p.m. Please excuse me if something comes up~] [Anti-piracy ratio: 60%. Thanks for your support o3o] Note: 1. The main story is in third person. A Bat-sis story. 2. The heroine only pretends to be sunny. She's not on the purely good side. The romance has different endings. 3. Lots of flashbacks, plot twists, and mysteries to solve. 4. Warning: The Joker dies in some universes, but survives in others. [Blurb for the upcoming story, "[DC Comics] Becoming Damian's Mentor":] Being Damian Al Ghul's mentor is a high-risk job. The League of Assassins requires him to kill his mentor on graduation day. That means not only will your student nitpick you in class and keep you under surveillance in your daily life, but once your lessons are complete, he'll try to assassinate you... You didn't volunteer to be Damian's mentor. When you transmigrated, the man originally meant to mentor him died right in front of you. The Demon's Head's son, who had come to become his apprentice, spotted you. You explained, "I was just passing by..." The black-haired, green-eyed boy's knife was still stained with blood. He raised it. "Since you're a nobody, then..." "To be perfectly honest, I'm the late master's prized disciple, and my skills are far beyond his. If you want to be my apprentice, I'd be happy to teach you. Anyway, don't be rash, little bro... I mean, big bro!" That lie came from you, who had no intention of dying in another world on the very day you transmigrated. Anyway, you survived and became his mentor. "The sound of your thoughts is annoying me." Your delinquent disciple stood in front of you, displeased that your thoughts were wandering while he was there. You could more or less guess what he was thinking: learn some skills from you as quickly as possible, then cut you down and find his next mentor... So on the day he was assigned his graduation mission, you faked your death without hesitation. In the end, he didn't kill you, and he didn't let go of your hand, either. ...Is something a little off here? Theme: Believe in justice.