Dark is a very old being, every time he ‘dies’ he reverts back into a small orb where he waits for someone to drop some blood or something with their DNA on it so that he can take a new form. He can change into any species with enough of their DNA and becomes a better version of the original (stronger, faster, smarter, etc.) The only thing that remains constant through all forms are the red and blue lines down his body. When he gets angry the lines glow, he glitches red and blue, and his skin gets scalding hot. While this doesn’t affect him, it does affect others that might touch him.
When he was captured by the federation, their intention was to experiment on him since he is the only one of his kind. He’s also a criminal, so they were able to do this legally. Their ship crashed though, killing all the occupants except Dark, who just reverted back into his orb form. Flash forward 40 or so years when Mark and friends are scavenging the ship for parts. Mark’s arm brushes against something sharp, his arm is cut, and he loses a decent sample of blood. Dark takes this as his long awaited opportunity to get a body again. It takes a few months for him to fully transform into what he assumes Mark looked like (he only saw him once but the DNA did most of the work anyways). He’s pretty close, but he’s a little more alien from Mark’s dad. His ears are pointed and his eyes are longer and thinner.
Next, Dark finds his old ship and readjusts to the changes the universe has gone through over the last 40 or so years. Despite this, he still puts on his old clothes because he likes them. Now, his mission is to find and kill Mark so that he can assume his identity.
