[@Chaotic Chao]: We are always open.

Unlike Kid Lanturn's game that has a similar premise as this one, there isn't any calling dibs on powers.  While variety is the spice of life, there isn't any restriction on what powers your character can have if another character already has a similar power.

As NMS (Nitemare Shape FYI) already mentioned, first read through the rules.  While they are really similar to the rules in All-Star Marvel, it is still a good idea to look through them.

Although we don't want you to just make "clones" of Marvel and DC characters, you can still take inspiration from them.  I give some examples with my characters.  A quick caveat before I begin.  Before I even found this game, I had already created all three of the characters that I am about ready to talk about.  So, I understand if it seems difficult to create something "unique".

My first PC is [b]Raptor[/b].  I would say that this character was least influenced by Marvel and DC characters.  Besides his claws that kind of resemble Wolverine's, minus the adamantium (although ironically he probably have only used them once through this entire roleplay), his theme is a play on the trope where heroes (or villains) have animal motifs.  Usually, these characters have powers that correspond with their animal motif (Spider-Man, Ant-Man, Wasp, etc), but the majority of them still look entirely human.  To play with this trope, my character here, in addition to having powers related to a Velociraptor, has physical attributes associated with that animal, too, such as a dinosaur tail and the signature foot claw.  His girlfriend, too, follows this pattern (in this case, features of a wasp).

My second PC is [b]Iron Knight[/b].  As his name might hint at, he is influenced by Iron Man (and a little bit by Batman).  Although there are some similarities between Christopher Arthur (Iron Knight's identity) and Tony Stark, such as being rich, using powersuits, being orphans, and having a butler and secretary, there are differences, especially in his backstory.  He doesn't have any technology keeping him alive.  He has a half-sister to take care of since their parents died.  He works with our game's version of SHIELD (something that, from my knowledge of the character, Tony Stark would have shied away from).  The important thing is, even though there are a few similarities, there are also differences that make these two characters distinct from one another (so you could make a Veen Diagram chart for them).

My third (and final) PC is [b]Arachne[/b].  Just like Iron Knight, you can kind of see that she was influenced by Spider-Man.  Having, if you were to examine her character, you would see that past her powers, she really doesn't have anything in common with Peter Parker.  She does not share a tragic background.  She doesn't have the same career path.  Her powers were NOT given to her by a spider bite.  Even her powers are a little different, as she follows Raptor's pattern.  In this case, her lower body is replaced by that of a spider (like a drider - spider-centaur basically - in certain fantasy franchises).

In conclusion, I would not recommend trying to model your character after [insert Marvel/DC character here] just because you want to play that character.  Instead, it probably would be better to mix and match ideas together.  A remember that you can find inspiration from outside of DC and Marvel lore, or even comic books.  We just don't want a character whose backstory looks as if it was ripped from a wiki page and the names were replaced.

Hope this helps!