Dragon Ball: Gohan Won't Study, and Even the Angels Are Crying!

In another GT timeline. After Sun Wukong left Earth, Son Gohan became its strongest defender. Now advanced in years and nearing the end of his life, Son Gohan believes he will go to heaven when he dies. But when he opens his eyes again, he discovers he has been reborn in the era when Majin Buu first appeared. Armed with memories of the future, Son Gohan resolves to change everything and make sure the regrets of the past never happen again. But as time passes, he realizes something is wrong. This world seems different from the one he remembers. Majin Buu has absorbed Vegeta and Sun Wukong, and after that, Frieza is resurrected, Broly appears, and there is even Beerus, the God of Destruction, who threatens to destroy Earth unless someone finds the Super Saiyan God. Faced with so many enemies, Son Gohan will never let them harm his family and friends. This time, he will save Earth!