YukkuReimu and Yukkurisa disappear from existence while YukEirin is trolling us

Yu-cat is an artist and also the nickname of her character. She began with a story about how Yu-cat's Yukkuri Yuuka was killed by Yukkureimu and Yukkurisa, followed by torture and death for those two yukkuri. Since this story, Yu-cat has been shown frequently with a bodied

Yu-cat falling for a Yuka-Chen while a Yukkurisa is tortured and a bodied Yuuka is not amused.

Yuuka (when she's calm) or a Flandre family (when she's on a rampage). There are a lot of yukkuri in Yu-cat's house, among which the Yukkurisa is always the one tortured and bullied.