In the rich text editor:
@PhantomLord
In a comment:
[PhantomLord](https://chowlings.com/user/PhantomLord)
For Names and Avatars:
In the rich text editor:
%PhantomLord
In a comment:
[![PhantomLord's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/PhantomLord) [PhantomLord](https://chowlings.com/user/PhantomLord)