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