Once Upon a Witch's Death: Serena

She's a human spirit of the Lapis' sacred tree that watches over its citizens for a long time. She cannot be seen by normal people but Meg can see her due to having special magical vision as a young age and noticed that she was a little girl despite being over 300 years old. She wanted to make some friends before she lose her sanity due to the magic contamination and eventually turned into a monster because of the tree was beyond saving which led Inori to burn it down but Meg didn't want that and went inside the tree to purified her and the tree. This is from Episode 9.

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