Can people know what characters i have?

For some reason a lot of guilds have a “only mains” rules.
I have 6 high gs deathblades so i was wondering if they can somehow know im not really using my main.
In global chat I selected so it showed the character that is on the guild

No they cannot. Although if you arent active enough for them they’ll probably just kick you.

technically, no, they wouldn’t know. but realistically, i don’t think they care if you do every guild task and dono daily on your character

They actually can tell if they can visit your stronghold, Stronghold Info lists the main character.

However like the above person said, they probably won’t care that much if you’re still actively contributing. I just wouldn’t join on an alt you only play with rested bonus.