Ok, so, for symbolic purposes, I’m kinda looking for a mythological creature (preferably a bird, or at least having feathers) that can serve as a counterpart antagonist for the Phoenix (or a character meant to symbolize the Phoenix here). But other than coming across dozens of mentions of cultural significance of ravens across history and culture, I’ve found nothing that feels like an actual match for the legendary bird of fire and resurrection. So, anyone has any recommendations? Also, just ‘cause I said “preferably feathered”, don’t hold back from presenting other options should you really feel they match the need.
Can you be more specific about what you're looking for? There are several mythological bird-like species. But are you wanting them to be associated with fire and resurrection? Or just a mythological bird in general?
I'm looking for one that could serve as the opposite of the Phoenix, so rather than fire and resurrection, more like something that would represent death and darkness.
I'm no expert in mythological birds but a quick google search pulled these up that may be of interest: https://en.wikipedia.org/wiki/Poukai https://en.wikipedia.org/wiki/Devil_Bird https://en.wikipedia.org/wiki/Lid%C3%A9rc https://en.wikipedia.org/wiki/Nachtkrapp https://en.wikipedia.org/wiki/Valravn
Have a look at a Chimera, that might be something along the lines of what you are looking for, hope that helps.
I'd say ravens fit the bill here. They can be associated with cold weather and death, which are opposites of fire and rebirth. But why not make your own mythological creature? A bird that inhales the breath of life? Or snuffs the fire of life?
In that case, there are Harpies, who carry people to the underworld. There are stymphalian birds, who have beaks of bronze and razor sharp feathers and poisonous dung. Wyverns are distant cousins to dragons and are often associated with cold and ice. An ala is a demon-like creature of air and storms, which seems pretty wicked. I'd look them up if you're going for an evil creature.
How about a great cormorant? I believe they're meant to be messengers of the dead and/or souls of those lost at sea trying to communicate. They're dark, dive pretty deep, strike stunning shapes when they're drying their feathers, and as sea birds they provide that watery contrast to fire.