Wendy is Barbatos, the god of wind.
In the Genshin game, there are seven gods who control different attribute elements. They are the wind god Barbatos and the rock god Rock King Dijun. The other five characters have not been announced yet. Among them, the wind god Barbatos refers to Wendy. As the god of wind, Wendy controls the power of the wind. As a bard who came to Mondstadt, her true identity is the founder of Mondstadt and the wind god of Sky Island.
The story of Barbatos becoming Wendy
Wendy has not yet become the wind god. He is just an ordinary wind elf called Barbatos, which is the image in the picture above. Like a mini version of the Abyss Master, he happened to meet a young man who was good at playing the piano and liked to sing poetry.
The two soon formed a deep friendship. The boy lived within the wind wall created by the lonely king of the tower. All he saw in his life were depressing and desolate scenes, not even birds. He had seen it before, and he wanted to see the birds flying freely. Barbatos also wanted to help his friend realize his wish. Just as the battle between the North Wind Wolf and the Lone King in the Tower intensified, the oppressed people also participated in the battle against the Lone King in the Tower. Barbatos and the boy also became members of the resistance and joined the battle together.
The resistance soon spread like a fire, and the attack from the Borei Wolf and the people of Mondstadt finally made the lonely king of the tower unable to resist. With a loud noise, the tower's castle collapsed, which also meant that the demon that oppressed Mondstadt finally ceased to exist.
Everyone has seen the High Tower Lone King Castle, which is the lair where the Wind Demon Dragon resides, which is also the Wind Dragon Ruins on the map. I believe everyone must have wondered why the Wind Dragon ruins looked like a palace when they went there, because this is the ruins left after the towering Guwang Castle was destroyed. Unfortunately, during the battle to attack the towering Lone King Castle, the young man died.
After the victory in the battle, Barbatos also evolved. He gained godhood and became the god of wind. After becoming a god, Barbatos still remembered the boy's original dream, to see the birds flying freely, so he transformed into the boy's appearance and inherited the boy's name: Wendy.
He used his divine power to summon strong winds to blow away the white snow covering Mondstadt, and sprinkled feathers symbolizing freedom. People built a city where the feathers fell, which is now Mondstadt. Baba, the god of wind Thos also became a religion of Mondstadt. Under Barbatos's admonitions, Mondstadt became a city without a king, advocated freedom, and became an unruly city.