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