Hi, all your characters look very intriguing. I especially like the blacklight sorceress, the fox spirit and the ocean spirit. So with that said, some character plot ideas.
Obsidian/Vyraena: I think these two could pair up well together because of the similarities in their magic. Obsidian practices moon magic, basically a combination of light and dark with a sky theme, but not the same as what you've got for your character. Obsidian travels around a lot so could very well meet up with Vyraena, perhaps in a library somewhere? Obsidian loves knowledge too and is on her search for self-realization through whatever means necessary. She is a kind soul and could get along quite well with your sorceress.
Turquoise/Coralia: A mermaid and an ocean spirit? I say yes! Underwater exploration adventures, or perhaps they are investigating some mystery underneath the waves, maybe even checking out a sunken ship from years ago that is overgrown with ocean plant life and partially hidden from view?
As for Miko, I am planning eventually to get a couple Thanati characters posted, so this one I think will have to wait. Let me know on the other two please, thanks.
