Lune has long, green hair with trimmed bangs and red eyes. She has two small horns protruding out of her head. She wears a sailor outfit with a lab-coat on top off it!
Lune has a hagoromo and a handbag, while her skull sensor is placed on top of the bag. Both of her legs, her right arm and her right hand are bandaged, with an addition of a band-aid on her left shin and a new bandage on her left hand. Lune's horns are set in a different way than the other demons shown, even though it still shows she's a demon of Old Hell. Instead of the ones seen on Fiore or Nora, the horns looks like the way the thunder-oni has their horns set.
Lune displays a masochistic attitude as shown that she is willing to stab and cut herself without care. She is also a bit lazy, shown when she gets annoyed and upset that she has to do rollcall, even though she did it a week ago. Lune also seems to have a sweet-tooth, since she once ordered a coffee with heaps of sugar.
When facing against any topic about the goddesses, Lune is not hesitant to be cruel and sadistic like Fiore, and is fully willing to kill all of Keima's previous conquest targets without any guilt or care, despite knowing that some of the conquest targets are not goddess hosts and it is against the rules to kill people.
Lune is undoubtedly one of the smartest characters in the series. She is able to roughly figure out that some of the goddesses are in Maijima High School and are all Keima's conquest by checking on Haqua's activity log alone and after some probing, she can even confirm her guess. Even Haqua says that she is "smart." Perhaps her high position in Vintage is a testament of her intellect.
Lune is rather good with spells as she is able to overpower, defeat and trap Mars without any visible injuries. In terms of fighting, Lune is also quite good. She is able to fight and defeat Haqua - who easily defeats other Vintage members like Gira - on equal footing and is even able to injure and pin the latter down with just her pen-knife while Haqua is armed with her Scythe of Testament .