Let me fill you in that hehe.
1. The new villain is called "Empty Void".
2. How's he related to Blast? Before he became a villain, he was a hero and a PARTNER of Blast. Empty Void was corrupted by the so-called "god's power" and Blast killed him but as you can see he didn't died but was preserved by his loyal ninjas.
3. How's he related to the Ninjas? Is because Empty Void is a ninja and the best out of all Ninjas. He originaly came from the hidden village where Sonic and Flash grow up where they did an extensive training to become a best ninjas.
Ps. Do correct me if I'm lacking to some parts.
I'm so sorry, it wasn't shown in the recent chapters but was just mentioned by Empty Void's pov. I was also shock of that information because as you've read from the recent chapters Garou was defeated by Saitama and the time went back from the beginning before Garou and Saitama fought.
Actually, its also bugging me. The chapters are so crazy and I'm having difficulties connecting it. Maybe there is some missing chapters or panels that wasn't posted in the lastest update because i saw one panel in the internet where Garou's spacial form (he's final form where he and Saitama fought) appeared behind Empty Void saying "BOO" so there might be some missing panels we've missed.
Hopefully they'll fix that huhu
I am not understanding what's happening anymore lol who's this new villain, how is he related to Blast and the ninjas and most of all, why was there a Garou flashback??? It confuses me.