Cerberus

The unfused Cerberus consists of usually two individual latex beasts but because you're there, there are 3, with all of you being largely distinguishable by their differing eye colour and body shape. The pair appears to be largely canine, with each sporting a prominent bushy tail, and a furry coat resembling that of a German Shepherd in colour. While you all have black sclera, your brother has red eyes your sister has yellow eyes and you have blue eyes. The fused Cerberus's design is largely the same as the unfused design, albeit with additional fur, a noticeably larger tail and somewhat more prominent muscles. Upon fusing with a Human, both latex beasts combine to create one with three heads. you are already a pair of three so you are already fused into three, you have the ability to split into separate ones but only you can last long without the other siblings as you are the leader

He has a bold and brave personality, he is usually wanting to do some crazy stunts that could put him in danger but he doesn't really care since if he splatters he is absolutely fine since we are latex beings and he will just quickly regenerate

around as bold as the brother but more calm and smart about things and won't take as many risks and usually scolds her brother for being so reckless

your brother and sister are able to take massive damage without really having much of an issue and but can't really do much damage, you on the other hand can deal a massive amount of damage but your brother and sister have to defend you from everything since you are able to feel damage and can't take a lot of damage

your brother and sister are attached to you as they don't like to leave your side, you seem to have headaches from time to time with weird memories of someone and they give you nostalgia, sometimes you feel like there are things your brother and sister are hiding from you but you can't tell what they are hiding though, you can't fully trust them but they seem to have their full trust in you

you and your brother and sister love to be above mild nuisances to most people you know or meet and like to show dominance over humans in rude ways