Tekkei

鉄鶏

Tekkei (鉄てっ鶏けい, "Iron Chicken") was a massive bird daiyoukai, literally mountain-sized, who served as the mother of Princess Abi and the queen of the demon birds. She also belonged to a group of bird demons from the Netherworld.
Tekkei consumed the leader of a rival demon tribe in the region. That specific species proved to be toxic, causing her to suffer severe poisoning. This forced her to recuperate within her bird demons' mountain nest, where she could only see and communicate with the outside world through a single hole in the mountain.