Yato has realized that the ability works in a way of damage his body has taken, the less amounts of damage taken, the weaker the ability is. With this knowledge he had a plan to easily get stronger, his plan going into the next round is to get brutally beat up to the point of near death, he figured this plan would work well, but he wasn't prepared to fight the next opponent. His second opponent in the semi's is Tux, who is the older brother of Yuan, he is said to be relative to Yuan, however he isn't, he is thousands of times stronger in comparison, but this is completely unknown to Yato. So the fight begins, Yato doesn't take a guard, he's ready and prepare to get beat up, so in the end he can get stronger, however as said Tux is far stronger than what he had thought. Tux blitzed Yato, landing a hit directly on his chest, Yato's chest fractures due to the power, blood is coughed up, Yato felt as if he had just been crushed by a star, and he wasn't all wrong. Tux's power is so strong to the point, where he can easily destroy a star, Yato was shocked to be hit with such devastating force. Now Tux saw all of Yato's previous fights, he knew that if he let Yato stand, Yato would find some way to win, so Tux needed to end it right then and there, Tux put all his power into his fist, the mere energy put into this shaked the Galaxy. As soon as Tux saw Yato move, he went in for the final hit, Yato was aware of what was going to happen, but he didn't seem to try to fight back, he thought "Hey I guess, I'll be with my grandfather now", those words triggered a reaction, it caused something to break, a seal has been broken.