In the rich text editor:
@yukino_hydra
In a comment:
[yukino_hydra](https://chowlings.com/user/yukino_hydra)
For Names and Avatars:
In the rich text editor:
%yukino_hydra
In a comment:
[](https://chowlings.com/user/yukino_hydra) [yukino_hydra](https://chowlings.com/user/yukino_hydra)