- Both take on occupations as heads of an equivalent to the PETA. They happen to house many exotic species of animals that people almost never see up close.
- Both can be united as one.
- They represent Night and Day.
- The light one (to the left) is called Sister. She's always eager to take control and merge with the other one. She's represented as almost cruel and bossy to her sibling. Her sibling is rather naíve and kind-hearted, and is also conscious while Sister takes over, but is unable to resist her. When they are merged, their appearances mix of each other. Sister's quote is; "Become one with Sister."
- Both can change their sex.
- Their animal parts of their bodies only appear at certain circumstances, and they can also develop completely different features along with it; such as animal faces, legs, etc.
- 320 are actually mythological gods, but were banned away from their kingdom when causing a disaster. This ended up with them being chained to each other, cursed to stay that way until they have cleaned up their mess. This explains their animal-like forms, which they also appear chained together when in that form.
- They are one spirit in two bodies.
- Neither of them are aware that their other side exist.
- Both of them are actually normal teens. Being twins, they're both mentally gone as they together fantasize about their own fantasy world. Everything is great, until they get seperated or when people try to bring them back to reality. Meds have a bad effect on their mental health.
- Despite what many people think the light one is kind and gentle and the dark one is cruel and aggressive.
- Most seem to agree that the left character is supposed to be female. However, the character to the right has been portrayed as both female and male in fanart and is often called "she" as much as they have been called "he".