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