Spoilers for One-Punch Man chapter 166 ahead!
After being teased, briefly appearing, and then vanishing once more, One-Punch Man's number one hero Blast is back, and this time, he's here to fight for real. But can this top hero live up to the mystique? Surprisingly, he can.
Blast was mentioned as the top hero in S class early on in chapter 30, but he doesn't make his first actual appearance outside of flashbacks until chapter 139. He first appears when Saitama, Flashy-Flash, and Oculette touch a mysterious cube, which puts them in contact with the evil God that's been plotting to destroy humanity. It offers them power, but Blast appears and prevents any of them from accepting it. He takes the cube with him, presumably to protect it, but is strangely unconcerned about the bloody battle with the Monster Association occurring just outside. He is also shown to have a team of other super-powered individuals that he works with. Through all this, the only power Blast uses is a dimensional portal, but his aesthetic suggests he is more of a technological hero than a mystical one.
When Garou reaches his highest power on his own, his fight with Saitama in chapter 166 registers on Blast's sensors as posing a threat to the planet, and he heads out right away to stop it. Unfortunately, he doesn't arrive in time to keep Garou from accepting God's offer of power, and the newly crowned Awakened Garou: Cosmic Horror form arises, emitting the deadliest radiation in the universe. With the other S-class heroes (except Bang) all suffering from that radiation, Blast is one of the only ones available to fight. After trying to reason with Garou, Blast begins to retaliate, using his portals in an incredible way to trap Garou, and very nearly succeeds.
Blast's first attack literally conjures the image of the symbol for infinity, suggesting his true power may be totally unlimited. Blast's powers are based around dimensional warping, which includes the manipulation of gravity. Like Saitama, Blast seems very concerned about the possible ramifications of using his full strength, which is a fair concern when dealing with fundamental forces of the universe. On the other hand, Garou also wields God's universal-tier power, so there isn't any choice for Blast but to use full force. For what is essentially his character introduction, Blast lives up to expectations. He's clever, insanely powerful, and even has compassion for Garou, recognizing that he's being controlled and attempting to spare him in the hopes that he can still be saved.
The chapter ends with an enraged Saitama and Garou going head to head, with potentially planet-shattering consequences. One-Punch Man has been on a streak of incredible chapters, beautifully capturing these battles between beings with god-like power as they toy with the forces of the universe. But if the Earth (and the One-Punch Man manga) are to continue, Blast will need to bring the full extent of his power before it's too late.