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