It's basically canon....

EININ confirmed it on Twitter and discord

And also this;

(That's Alone)

Yeah yesterday was fucking WEIRD on discord

Like

WHAT IS THIS

WTF ALONE

anyway, the actual ship is alright. All though it's entirely possible that Alone is abusive towards Einin, but she says he's a retard so it's still not okay.

Update:OKAY, SO ALONE DOESN'T ABUSE EININ! It's not an abusive relationship, false alarm.