SO yeah Illiendi goes off to woo mum or chat with Eldest brothers wife and said bro's all OMGZ REVENGE! He sneaks into Amano's room expecting him to be asleep but Amano isn't, maybe he's worried about Illinedi boning mum or possibly attempting to screw the pretty delicate wife. Of course Illiendi wouldn't do the latter unless SHE begged/asked so. Anywho, in comes evil mcevilness. Shuts the door quietly all stealthy ninja like and turns to see Amano at his desk not in bed. Amano for some reason assumes it's Illiendi back and addresses him somehow 'you didn't have too much fun right?' or something along those lines. Only for brother to lunge at Amano with a kitchen knife or small letter opener or whatever it is we feel like at the time. There's a struggle, Amano dodges two slashes and rolls away from a third, the room being loudly trashed of course but manages to sustain a surface wound and fell in such a way he can't easily get up. Brother goes complete psycho and lunges at Amano. Amano covers his face but nothing happens and when he opens his eyes from tip to hilt is buried into Illiendi's side. Illiendi's all 'oomfg my suit' but basically fine even if he does have a massive dagger/weapon in him. At this point he spots the wound on his master and is all 'oh no you didn't!' and literally grabs the brother by his neck and throws him like a kid tossing a rag doll across the room. Then he'll follow him, demony bits seeping out a bit because he's unhappy. And holds said bro up off the floor by nearly a foot and starts squeezing his chump throat. Amano steps in and tells him to stop, Illiendi will hesitate in doing so but will stop and then bros all 'he tried to kill me!' and amano's all 'yes he did...and just remember, I let him try'. Or something like that. 

Now come morning obviously bros all shook up but there won't be a mark on him the room will be fine and clean (illiendi awesomeness) and so no real proof so its the known 'drinker's word against the new family favourite so he stays all quiet like but a little terrified, might even be a tad respectful at breakfast which might raise a few eyebrows lol.