Wondering what is known of the 3rd Moon (hidden moon?)

Eporem

in this era of ESO..

thanks in advance for insights of this...

VoidCommander

Third moon doesn’t exist yet in ESO. Mannimaro assends to godhood as the Necromancer’s Moon later on.

VaranisArano

Well, ESO features the Dark Moon, the path of Lorkhaj in the final AD quest in Reapers March.
https://en.m.uesp.net/wiki/Online:The_Den_of_Lorkhaj

There's also this book talking about the Hidden Moon: https://en.m.uesp.net/wiki/Online:The_Tale_of_Three_Moons


Otherwise, since the third moon seems to mostly feature in the lore regarding the Mane, it might be worth looking at the Reaper's March questline and Pridehome in Southern Elsweyr where the "forgotten Manes" lived.

Eporem

there is this as well said about Azurah - The single moon Azurah carries is in her right hand, the stone of commitment mentions that souls were guided by the adepts of the hidden moon to the position of her left - which is her star (soul gem?)

I have to do the quest still in Southern Elsweyr - maybe there are more answers there..

edit:
and I can imagine this Moon being called the Necromancers Moon in the future (if it is the same third moon as was in the past era (hidden moon) and this era (dark moon)).