Shironeko

Shironeko (シロネコ) is a character in the Isekai Shoukan wa Nidome Desu series.

Beast Fusion
Shironeko and Mineko's secret weapon where they are able to fuse together

Mineko
She is Shironeko's younger sister.

Etymology

 * The name Shironeko means "white cat" (シロネコ) in Katakana.