Ultraman: Reborn as Belial's Son, A Father-Son Bond Like No Other

Out of sympathy for Belial's misfortunes, the male protagonist accidentally transmigrated to the Land of Light, where the System made him Belial's eldest son, even though Belial supposedly didn't have one. The protagonist originally wanted to change Belial's history, but soon found he couldn't. Belial had already been locked up, so he had no choice but to start making plans in advance. Through his own efforts, he established the Galactic Empire and the Land of Darkness. The dark giants from 30 million years ago? Lu Xiaobu: “They're my underlings.” Jugglus Juggler: “Lu Xiaobu is the guiding light on my path forward. Red, prepare to die! Huh? You've joined the Land of Darkness? Oh, then we're comrades in arms!” Zero? Lu Xiaobu: “I talked him into a downward spiral, and now he's never coming back from his path of making his father suffer!” Geed? Lu Xiaobu: “Kid, if our dad were the protagonist of a novel, he'd be the most miserable one of all. You still want to fight him? Is my Fangtian halberd not sharp enough?” Geed: “I'm sorry, Big Brother. I was wrong. I'll help you attack the Land of Light right away. The King's power? I don't want it anymore. Nothing beats dear old Belial! Be sure to bring me along when you fuse into Saga. Not for any other reason: I just want to improve and become fusion material!” [Multiple heroines + A son who makes his father suffer or a devoted filial son? + A male protagonist who keeps switching sides: light or darkness]