MunaZaldrizoti

Sirens already exist as Event Creatures so I feel you'd really need to make it different from them for it to be good.

I think it would be much cooler to instead make it almost like a curse, like people with the CA could live outside of water, but would have to be in water every X days and when not in water their skin is dry and they have a drive to find water, Possibly have them have permanent gills and a "fish-like face" to avoid them form being "beautiful creatures" because honestly having a weird CA that is beautiful will lead to some RP that does not need to be on the server. I can't think of any positive things that could be done for them that aren't already done though. 

You also have the possibility of doing a Murloc-like CA which could also be really interesting due to the lack of intelligence. 

mermaid/siren CAs will never work in lotc bc no one likes rping underwater

There should be options for both more lighthearted concepts in addition to darker ones