I've been speedrunning a ton of Refs recently
Backstabbed (Neph's Lore)

Yeptin and Jasper are Twins, and Pintica is their younger sister. Their father is Xelphin, which is also Neph's uncle.
Also, random fact, Neph is considered a "Faceted Nephalem", meaning she has both an angel and demon side (named Squette and Klexin). The other three kids are both considered Nephalem as well, but they are classified as "Merged Nephalem".