[Divino]

Originally Posted by 7Th

Spoiler:

Except this episode confirmed that Aria cares more for Eden than she does for Kouga...

Not to mention that Kouga and Aria are definitely twins; they came from the same meteor, dude.

Spoiler for spoiler:

How does she care more for Eden if she literally betrayed him and chose Kouga is wish to destroy the ruins instead? What looked like concern was probably just guilt.

Also Shaina never mentioned that Aria was Kouga is sister or that they were related.
I think at least a "you share the same blood" would have been more clarifying.
They might be the same species or from the same planet but they aren't siblings or twins until they explicitly state that it is so in the anime.