The Red Death is an evil speedster Batman from the Dark Multiverse. He got his powers from absorbing his universe's Flash. Eventually, during the second Dark Multiverse crisis, Barry temporarily regained control and became the Reverse Red Death!

Good question!

I really don't like the Steve skin for "normal" sized characters, like Captain America or Batman. I think the Steve size looks really weird. So, instead, I used the Alex format and add musculature that makes it look bigger, but still, IMHO, more normal-looking than if I were to use a Steve size.

I use the Steve size for characters who are, in the source material, much larger than normal humans. That's why my only skins who use the Steve arms are Darkseid, Thanos, and Swamp Thing, who are much bigger than humans.