Based on Greek/Roman Mythology
Phoenixes are birds of fire that look akin to larger versions of the shoebill stork with russet feathers. Like their smaller brethren one must bow before them/in response to them/mimic their greeting in order to gain respect of the bird.
When a phoenix dies it turns to ash and if the ashes are kept in a safe place, it will be reborn. After it's hundredth death/rebirth cycle it gains the ability to turn into a human form.