The Self Insert

Not to be confused with the general act of self insertion.

An in-universe character who is meant to be an avatar of the creator. This character often resembles their real-life counterpart strongly with some aspects that make them who they are: their physical appearance, beliefs, practices, and so on. The Self-Insert might even be the creator directly, sharing the exact name, appearance, and overall characteristics. A Self-Insert is related to a Self Reference but is more extreme in how it brings people from real life into the world of fiction.

There are few differing types of Self-Inserts. The most prominent type of Self-Insert is the Mary Sue, an unrealistically high-tier Ace-like Hero who can always bail their creator's creations (the other characters or the world) out of danger with very little effort, has All The Girls, and is rarely ever seen on their knees before their enemy. This can be a creator's sign of Utter Desperation as their real life might not be nearly as good as they make it in their own work of fiction.