@Warrior-_-Diamond They're called neopronouns! they're not super common, but some people (especially neurodivergent and/or nonbinary people) use them to express what their gender is to them.
cloud/cloudself and void/voidself aren't the only neopronouns, people use a lot of nouns as well as things like xe/xem and ey/em.
(I'm glad you asked btw, I'm always happy when people try to understand things like this rather than rejecting them immediately)