User blog comment:Jamintheinfinite/Subnautica Creature Evolution/@comment-35546951-20181011183756/@comment-28450065-20181011184547

Having an eel-like body doesn't mean it's related to the other eels. It doesn't share anything in common with the living eels, whilst it possesses some shared features with the dragon.

If it is a relative of the Emperor and dragon it is most likely not close to them at all though. Probably split from them a long time ago.