Tekkei (鉄鶏, "Iron Chicken") was an enormous daiyoukai bird, as large as a mountain, who served as the mother of Princess Abi and the queen of the demon birds. She was also a member of a group of bird demons from the Netherworld.
Tekkei consumed the leader of a rival demon tribe in the region. Unfortunately, that specific species turned out to be poisonous, resulting in her being severely affected by the toxins. This forced her to recuperate inside her bird demons' mountain nest, with only a small opening in the mountain allowing her to see and communicate with the outside world.
(Source: InuYasha Wiki)
