I'm going to try a little something different called, "Doing more work than you have to that no one is ever going to notice so that its harder for yourself and it takes longer than it should." Speaking mostly about the alternate-universe versions of Invincible characters as they appeared in Brit 10. They only appeared three or four times, mostly less, but I went ahead and designed them taking into account a whole backstory based on specific points-of-divergence from what readers know about them from normal Invincible continuity.
This character is Hex Splode, the parallel to Rex Splode, but you know, evil. His backstory, for reasons to be revealed in the Rex Splode miniseries, has more to do with Atom Shiva's and I won't get into them for obvious reasons. But since I've already posted Atom Shiva, I'll tell you about her for free. Uh, spoilers for the Atom Eve mini and Brit series if you haven't read them.
In this continuity, Eve's creator, Dr. Brandyworth, is caught by Director Stephenson and thrown into jail. Since he fails to make numerous appearances to Eve throughout her life, a subtle connection to him does not develop. When he finally manages to escape and find her, he leads his superiors right to her and they're both caught. When Brandyworth, as a complete stranger, is murdered in front of her she does not experience the temporary release of her full power and her mind is wiped. She is then trained for her original purpose, GDA's deadliest living weapon. She takes on the name of the goddess Shiva, whose opened third eye will destroy the world. Though amoral and ruthless, she is not evil and works dutifully alongside other GDA agents Donald Ferguson, Brit and Britney. Surviving the Geldarian War, she takes her spot at the Emperor's side as one of his most reliable enforcers.
But getting back to Hex Splode, I explained to Rex Splode mini-series writer, Benito Cereno, my idea and asked him for suggestions for how an evil Rex would look, because at the time I was kind of clueless. He said something like "Nazi Rocketeer" so I went on that. I put him in black leather even though I was worried it wouldn't relate to the original without the colors and popped his collar to resemble the collar on his original costume. Lose the cowl and slap on some WW2 Nazi goggles and then you've got a Hex Splode!
AKA tl;dr lol