My New Life- Why?

Yui lives with her twin sister and her friends but isn't she suppose to be living with the Sakamakis, that's the problem because they are all murdered and now dead, no one knows how they died. Cordeila turns up, they fight for Yui and Cordeila is defeated and Cordeila joins their group and learns a new life and with KarlHeinz there's romance. Wait the Sakamakis are alive now!