Xisuma, a voidwalker, can't breath overworld air. It's a curse, it really is, the helmet makes him look more scary than he actually is and the Hermits can't read his expression that well due to it! To Xisuma, it's a curse, something to be shameful of, something he avoids talking about. His parents didn't do much to assist him, simply telling him that he'll "Grow out of it" (Shouldn't he have already grown out of it? He's an adult for crying out loud!). He feels better in the Void, without the mask, but it's so lonely. It's cold and empty, and since almost none of his friends can breathe in the void, it would continue to stay like that for many years to come.
Pix grew up in what most hybrids called a "Human District" (Think of how our world is set up). He grew up with a decently well off family, getting into College, studying to be a doctor like his parents wanted, until one day he hid in the restricted books section. Upon that fateful day he discovered a book, detailing hybrids and all about them. Normally, Pix would have found this information interesting, but the way this book dehumanized these players felt.. wrong. Pix soon left the human district, fleeing to a server called "Empires" where he would remain for a while. He was the servers local human, and that attracted the attention of a fallen deity, a creature that had been watching over their world, the Vigil, it called itself. The Vigil was a watcher, as Pix now knew, and he would trade anything to go back, to not feel the suffocating void the Vigil trapped him in.
It was in season two of Empires that they met. Pix had become an archaeologist, and Xisuma wanted to see what the fuss was about this "Human turned Non-Human" (Pix could now survive in the void, after all, not just any human can do that). Pix was nice, and Xisuma felt himself open up in a way that he hadn't for many many years. They continued to stay in contact even after Xisuma left Empires. They eventually started dating, and when Pix first joined Xisuma in the void, it felt so freeing. He didn't need his mask anymore, Xisuma was free with Pix.
It's only one person, but maybe that's what makes it all the more special. The one person that Xisuma can truly open up and be free with, and the one person that understands Pix in a way others can't.
It also turns out the void is a very fun place to kiss in.
