Board Thread:Questions and Answers/@comment-30751547-20170207174415/@comment-4905541-20171021110829

Reading the comments, I think I'll support the idea of Saitama actually being Blast as well for a guess. This is because of a few facts.

One. This is ONE Punch Man. It's an established fact that our MC can end anything he wants to end by using just a single punch.

One. This series is in the parody genre based on Superheroes which when you look at it from a Japanese person's POV would be coming from western comic book heroes. Given it's not a tokusatsu parody completely, but incorporates characters like that at a minimal extent while going full on with the concept of popular western superheroes.

One. When we talk about western superheroes, it's a given fact that most of them, sooner or later, end up tackling plots that involve traveling in time or doing something that causes a similar effect in order to affect the time line of the story.

One. Blast's appearance was obviously designed to look similar to Saitama's with a "fiery/skewed appearance" in variation.

One. Blast is not present (which is why we're all playing hit-or-miss with our guesses for fun) anywhere in the story except only in Tatsumaki's flashback.

Now, if ONE actually intends to do a parody of western comic book heroes including altering time in the plot, there would certainly be a possibility that Saitama or an alternate world's version of himself would somehow find himself travelling back in time (or at least during that time line in Tatsumaki's past recollections) and doing his hero hobby without any care regardless of that fact. Considering the fact that Saitama has the possibility of limitless power, he could very well be able to put himself in a situation where he winds up back in time or another parallel universe. And just like when superheroes like the Flash and the J.League eventually find themselves returning to their designated time lines in the end, it's highly possible that Saitama who was known as Blast at that time was also able to return back to his own time line after a boring hero-spree (imagine how he reacted when he went to the moon and back, right?).

It's just a side idea, but maybe the reason why Blast's costume looked the way it did in Tatsumaki's flashback was because the force keeping the multiverse in check was actually in the middle of pulling him back to his own time by that time. I think Tatsumaki has been shown to be able to perceive forces normal people can't like Telekinesis or a person's aura and it might be what made her see that version of Saitama/Blast's costume--a visual representation similar to how people see the flash as a flash of lightning or a guy with red blurs coming out of his body. Considering we can't have two heroes literally smacking the entire universe into obliteration with one punch existing in the same place at the same time, I think it's a possible idea. And a good one given ONE's sense of humor.

Like:

Saitama: *Finally meets his parallel universe alter-ego Blast.* Ah... You're me.

Blast: Ah... It's me... But you're bald...

Saitama: YES! THAT'S RIGHT! I'M BALD! Give me back my hair!

Blast: Um... Nope...

Saitama: DAMN IT!!! Enough! Just go back to your own world, would you? (Seeing my hero self with hair is irritating.)

Blast: Ok... (Leers in his mind.)