Since Kristin is canonically the Goddess of Death, I imagine that she lives in the Void

Kristin can visit the mortal realm on Halloween, De la de los muertos (or Day of the Dead), and on her birthday

While Techno isn't related to Kristin, Techno does see her as a sort of motherly figure, and is kind of entitled at times since Techno remembers her, but Wilbur doesn't

Since Kristin is a Goddess, she can live for a very very long time, just like Phil and Techno

Kristin was banished into the Void after an accident occurred to Wilbur when he was very very young, and caused his premature death, and Kristin made the 3-Life system—and reset baby Wilburs lives bc yeah (based on a comic made by Tumblr user clacy2812)

Kristin was banished to the Void when Wilbur was about 3

Phil blamed Wilbur on Kristins banishment (even tho he wasn't doing the basic duty of making sure his 3yo didn't die by watching him)

Techno considers Phil as an old friend, but considers Kristin as the mother he didn't have

Techno is related to Huitzilopochtli (the Aztec blood god)

Huitzilopochtli basically said to Techno "yo, wanna be a badass unkillable god?" when he was dying during a war during the medieval era

There a lot more, but I'm sick and able to pass out, so here. This is mostly Mumza but idc. Have some Mumza lore food.