Dainsleif is an upcoming playable character and he will be added with Chapter ? The Dream Yet to Be Dreamed. You can see him in Genshin official trailer.
Photos are leaked by Lumie.
He was mentioned at TGS2020 Genshin Livestream first (check 47:20 in the video).
According to the video, he uses sword. The name of his region is revealed but the details weren't yet.
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