A while ago, people were debating on reddit about each of the primordial demons and if they exhibit traits that can be classified under each of the 7 deadly sins. Figured that since there's 7 demons and they're like the top-notch demons, it makes sense, so here's my take（´ 3｀). Considering I don't have reddit, I figured I should put it here!
> This has no relation to the sin skill series (except Guy)
GUY - Pride, TESTAROSSA - Gluttony, DIABLO - Lust, CARRERA - Wrath, MIZERI - Envy, ULTIMA - Greed, RAINE - Sloth
The most obvious to me were Guy, Testa, and Raine.
Guy has the ultimate skill 'Lord of Pride', and although Testa was stated to be the most prideful of the demons, she shows more traits of other sins compared to Guy. Guy's pride is so powerful that it literally manifests into power. Do I need to elaborate?
For Testa, I had actually debated with Wrath before going with the more accepted option; gluttony. She speaks about the taste of souls and spends the most time "preparing" her meals compared to every other primordial shown. This is especially shown in Volume 13.5.
Diablo, although he does not show sexual desire, I believe is best suited for lust. His unique skill, 'Tempation', which is all about desire, definitely made this easier.
Carrera's short temper is a key figure of her personality, her explosive magic making this much clearer. I feel that wrath would be the most applicable to her.
I gave envy to Mizeri through the process of elimination. I dont know enough about her character to really assign her to sin, so I believe this was the best choice. I'm a Mizeri fan, so I'm really hoping to do a character dump of her soon!
Ultima was a lot harder to assign than what I was expecting! I eventually went with greed for her. Ult really wanted that physical body.
Raine is stated to be a lazy subordinate. She often attempts to avoid work, and this has led her to trouble on numerous occasions. Although only showed once, she has been told off by Guy for this behaviour. Honestly, she is the only primordial I could associate with sloth, and as such, I believe she is most suited.
I love the primordial demons so much we need for interactions with them. It's not a want it's a NEED!!
