Wedy is sort of a pet name this Blodeuwedd was given by his ward, the Sproutling. He is protective of her and taught her many things, but unlike her he is not as naive. He is also much more loyal to the Verdant Mother.
"Tamiko cannot help but think of Nymphs, but while those tend to be beautiful forest creatures, this one is... there is no other word for it: ugly. Then something clicks. Not seen often, but you recall Nymphs having... a counterpart, one that shares the same connection to the First World, often spoken of in comparison to the Nymphs, but yet a creature so dramatically different. Blodeuwedd they called them. A forest guardian, whose connection to the First World makes it live almost between the two realms."