Board Thread:Questions and Answers/@comment-26000108-20150430060634/@comment-26076447-20150509034737

Not too sure about this but most likely not since they are vampires and not first bloods then again who knows though they would be second cousins if they were related in anyway.

Cordelia is directly related to them because Carla and Shin were her mother Mēne's niece and nephew. Mēne was their father's Gisbach's sister. Cordelia was Gisbach's niece as well. As for Ayato, Kanato, and Laito, they most likely have no relation to Carla and Shin even though Cordelia is their blood relative.