Each Noir had a master they served, once they became a demon they started to consume their master magis which led them to forget who they are.
They crawled underneath the ground, flew in the air in the midnight searching for their master before they forgot,
once they did, they will searched the blood similar to them, they will grew hideous fangs and figure resulting from bad memories they tried to remember.
A crawled noir is a fairy which haven't eat its master they stuttered in speaking.
A winged Noir is a fairy that won over a soul fight but refused to used the master's body. They talked fluently and obsessively killing other master's for their magis leaving tje crawled fairy to be stupid forever searching for their owner.
As a result, the crawled noirs often attack ordinary people and eat them.
A Goat-like noir with four wings on shoulder and hips, picturing the origin wings of Naekai is an intelligent Noir. They won over a soul fight and only eat its master. But sometimes people with strong magis power inclusing a lost human being.
Once a master win over the fight, noirs cannot touched them, but sometimes the Goat-like noir like to teased them.
And believed it or not, Angelo soul was ripped apart and he became one with the Goat-like noir. He's the one who sat on the trees watching her niece dragged by low level noirs - "she's the reason I died" He groaned yet grinning.