It makes basically no sense but I almost expect this to be half of Angelica, or something. We know that the Valkyrie was "struck down because she was a servant of demons", which was implied to be falsehood, but it could be something like a weird half-truth where she was possessed. That then begs the question "who's Haruka's Angelica then", but she could be Angelica's soul inside another body. After all, iirc current-Angelica is in a body which Haruka used some sort of skill/ability to regenerate, she was just a skeleton when he actually found her. So maybe he like, restored a fake body to her soul, but this is her actual, for-real body.
This is just me tinfoil hatting. It's incredibly unlikely, lmao