Creature Commandos reminded me of some old Worm OC's:
Some dude with too much ego and too much money buys a cauldron vial + a nemesis case 53.
The case 53 is nothing more than a cracked torso and head without a lower jaw that consumes whatever it's in reach to create a black goo that uses as limbs. Mentally it's no smarter than a dog.
The guy gets a physically enchancing light power and tries to start an heroic career as Radiant.
He debuts and kicks the case 53's, dubbed Python by the media a couple of times. But he gets too cocky, starts taunting too much.
He calls Python slug. Python remembers the slug. The cauldron failsafes fail for a fraction of a second.
Maybe it was the dead shard overriding it? Maybe it was the little acidic black goo burning just in the right place?
It doesn't matter, Python beheaded Radiant with it's maw.
Now we have a grieving woman, sister of Radiant. She is trying to figure put what happened to her brother.
She is found by cauldron. They don't tell her the truth, they just offer her a way to have revenge.
Cauldron sees the case 53 as a possibly valuable asset so they let it be, but the results of Radiant were pretty good. They give the same vial to his sister, she makes cosntructs of burning light.
She finds the feral Python eating out of a chinese restaurant's trash. And the cat and mouse game begins.
It starts as a hunter going for an animal, but eventually it evolves. The conflict and consuming more stuff makes Python smarter. Little by little it starts getting better at imitating how normal people act and look.
Eventually it... him, starts also going after her. It becomes a constant in both of their lives.
Python joins a team and Radiant joins whatever group is trying to take them down.
Sometimes she joins a hero team and Python and a bunch of randoms start a crime spree.
Radiant and Python start enjoying battling each other. Dead shards doing post-mortem conflict drive maybe?
Then it morphs into "only i can defeat you".
Eventually Radiant discovers the truth... and it doesn't really change anything. The rivalry has grown far beyond the nemesis bullshit.
Because in some fucked up way it's great to know there are someone out there that gives a fuck about you, even if it's in the most twisted way possible.