Board Thread:Speculation House/@comment-70.15.114.195-20151102160225/@comment-25396609-20151102161017

Yang has Taiyang's family name because her mother abandoned her at birth.

Surnames are not inherited by birth, rather they are whatever the parents write down on the birth certificate.

The creators have confirmed on numerous occasions that they are half sisters.

You are an obvious troll of questionable sapience.