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