Global Class Change: I'm a Level-One Synthesizer Making Hydrogen Bombs

[Invincible from the start, bewitching female emperor, no System or cheats, not a transmigration or rebirth story] The cosmic battlefield opens, forcing everyone on Blue Star to join the fight. Everyone can awaken a class at the age of 18. They use their classes to defend their homes and country. While others beg someone to carry them, Ye Tian blows up dungeons with hydrogen bombs. While others struggle to survive in dungeons, Ye Tian slaughters them with a Gundam. While others agonize over how to complete their class-change quests, Ye Tian is already at the top of the Gods’ leaderboard with his wife in his arms. The alien races of other worlds: “He’s too brutal! He wiped out an entire race without saying a word!” The monsters in countless dungeons: “That monster! He just tosses hydrogen bombs in and blows up the whole dungeon!” The nobles of Blue Star: “This guy is the ultimate winner in life!”