The Entities name is Moeru. This Form is somewhat friendly and he shows himself like this to people he likes and approves of. His form changes depending on his feelings/opinion towards someone.
Akuma doesn’t wear this belt usually because she feels like it restricts her movement. But if she has knowledge about an upcoming mission and/or knows that an event is far more dangerous and difficult than usual she grabs this belt and puts it on.
Pretty white Gloves that she has since School already, since she was in Second Year to be exact. The mechanism relies on the heated air that is created around Akuma by her Quirk.
This Mask is usually dangling around Akumas Throat but this item isn’t just for show. It’s actually a Gas Mask which specializes in filtering the air from smoke and particles. It also has the ability to cool off surrounding air.