Black is one of the original five symbiotes hewn from Spectrum. He's rather arrogant, very rude, but has a soft spot for his "sister" Green.
Well. He's a symbiote. So he's basically just a black blob when outside of a host. When his abilities are used, they have a black color scheme. As in, the tendrils grown from the host would be black, as would the bladed whips the host's arms turn into. Black identifies as a male.
Black is incredibly arrogant and views many people as below him. Even though his life literally depends on living within another being, he can't seem to grasp the concept of someone being his equal, let alone better than him. He's often derogatory to just about anyone he meets, including his host. Of course, there is one person he brings out his nicer side: his sister, Green. He cares very dearly for her, and would do anything to ensure her safety.
Black is ambitious. Probably overly ambitious. Black wants power. He wants to be a leader, to take over the world, or at least one lousy kingdom. The problem with all of this is Black needs a host, so he could never be the sole ruler. And even if he did not need a host, it is doubtful a blob would be accepted as anyone's king. Still, he continues to delude himself into believing that his dream is a possibility. In his mind, he is already king, and everyone else is just a peasant.
Like all symbiotes, Black simply found himself "awake" one day, with two thoughts in his head: "find a host" and "Spectrum." He had no idea of his abilities. He just knew he was Black, and he had come from the Spectrum, whatever that was. Still, he spent his time going from host to host, simply staying alive, looking for a purpose. And then, one day, he saw it. As a crow sitting on the wall he saw a man who was far superior to the rest. He saw the king of the small kingdom he was residing in, festooned with jewelry and fine garments. He was like a peacock among pigeons. Black decided then and there that this was what he desired. He wished to lord over others, to become a ruler of great wealth and standing. He had found purpose.
Black eventually made his way to Kritana. He had considered using that king as a host, but he decided he could do better, that he would do better. So he traveled, looking for a host that would truly be right for him. In Kritana he met the other five original symbiotes, along with Rakav. Black found himself being very Protective of Green, though he did not know why. He also grew to hate Rakav, perhaps because the Draconid knew exactly how to belittle him, to cut through the clouds of delusion Black had surrounded himself with. And of course, Black, like the rest of the symbiotes, grew to fear Red.
Black spent much of his time going from host to host, either causing trouble for Rakav, or using Rakav as a host and helping him. The latter he usually did for the sake of Green, or simply to try and destroy Red. He was also a host to Korsakov several times, generally so he could help the madman attack Rakav, their mutual enemy. His genetic material was also used, along with Rakav's and Red's, by Korsakov to create a host-less pseudo-symbiote to wreak havoc on Kritana.
Eventually Black decided to leave Kritana to continue his quest to find a worthy host. He ended up in Drealms and once again temporarily helped Korsakov fight the Dark One. Although he abandoned Korsakov as soon as the going got tough.
Green - Cares for her very much. Incredibly protective of her. If anyone should harm her, expect Black to exact a terrible vengeance unto anyone who would dare harm his sister.
Red - Black is terrified of Red, though he tries not to show it. Black views Red as a monster, a symbiote that must have been created by mistake.
Rakav - Black dislikes Rakav very much, and would generally do whatever he can to harm or undermine the Draconid.
Blue- Thinks of him as Rakav's lackey, since he basically agrees with whatever Rakav says and has settled down in Rakav for quite some time.
Silver - Silver is incredibly quiet, so Black never really notices him.
Korsakov - He thinks the man is an idiot, but he occasionally makes an okay ally.
Forett - Never going within a mile of that guy again. He's almost as terrifying as Red.
Lark - Well, he's a little odd, but as long as he's willing to listen to Black, then Black will be okay with him.
Bladed Whips - Can allow his host to turn their arms into bladed whips. The whips are only slightly longer when the host's arms were when not being swung, but can stretch out to very large distances. The blades on the whip are about as strong as normal steel.
Tendrils - Can allow the host to grow tendrils anywhere on the body that can stretch to incredibly lengths. Unlike the whips, the tendrils are completely controllable. i.e. The whips must be swing, and can even be extended like a hookshot (or some better example of a real thing), but the tendrils could be made to wrap around a foe or tie themselves in knots.
Symbiotic Enhancements - Like any symbiote, he increases the speed, strength, and durability of his host.