Don't Run, Boss! Let Me Borrow Your Ultimate Move

(Boss fights + No. 1 on all kinds of leaderboards + guild wars + national wars) (There are female characters, and this is not an utterly invincible power fantasy. Please take note if that’s not your thing!) Everyone changes class, and ten billion people from Blue Star are randomly sent to another world. The unfortunate Wang Man has barely transmigrated when he runs into a major boss. At the brink of death, he awakens an SSS-rank talent: Borrow and Repay. By using up all his mana, he can borrow a boss’s ultimate skill. He decides when to return it. Even better, once he borrows a skill, he gets it, and the boss loses it. The only catch is that the longer he keeps a borrowed skill, the higher the price he has to pay when returning it. He might even have to pay with his life. Wang Man’s imagination runs wild. If he borrowed it with his own ability, why should he give it back? If he kills the boss, then there’s no original owner. Does that mean he won’t have to return the skill? And so, a boss slayer is born. A boss’s Bloodbath skill grows more powerful as its health drops? Great, it’s mine now. A boss’s invisibility skill makes it invincible? Great, it’s mine now. A boss’s forbidden spell can destroy heaven and earth? Great, it’s mine now. Tremble, bosses! Your god has arrived. I’m not just borrowing your ultimate skills. I’m borrowing your heads, too.