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