In the rich text editor:
@Xciel0
In a comment:
[Xciel0](https://chowlings.com/user/Xciel0)
For Names and Avatars:
In the rich text editor:
%Xciel0
In a comment:
[![Xciel0's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Xciel0) [Xciel0](https://chowlings.com/user/Xciel0)