The fox woman Issei encountered was running away and climbed a tree in the familiar forest, she was still in her fox form and looked at the mushroom cloud that was created by Issei. She looked on in awe and changed into her semi human form. She was still wearing Issei's jacket, she loved it as it has his scent on it and that he was truly decent, every man would love to see her in the nude but Issei saved her from embarrassment and death. She watches from a distance and sees the others with him.
Woman: who are they and why does my other half seem so distant from them?
She didn't like seeing them with him.
Woman: I can feel your anger towards them... except for one....is she your mate?...no you don't have what we have with her.
She watches everyone talk about something, something missing then they teleported away just after she saw Issei take the mask.
Woman: no no no. Not that.
She was getting worried and dropped to her knees, she felt something move around in the jacket, she took it out and saw a switch blade.
Woman: what's this?
She started to examine it and accidentally flicked the blade.
Woman: a small blade? It belongs to him. He has good taste, just what I expected of my mate.
She puts the knife in her pocket.
Woman: I wish I got to know your name at least, I'd be one step closer to knowing the truth.
She transformed back into a fox and was on her way to find him. She could feel his presence to an extent even though he teleported away. The woman managed to create some clothing using magic and fixed his jacket too, no bite marks and blood on it, she felt guilty for hurting him. It was a thin jacket that was meant for style in the summer. One day she was wandering and she felt someone's hands on her face.
Woman: what the? Who's touching me?
There was no one around her and no presence except for one.
Woman: wait...these are his hands, they are so gentle, I can sense his presence.
She was feeling Issei's hands touching her cheeks and her lips. Issei was in his room at the time with the door locked at touching the mask.
Woman: what are you doing?...wait stop!!
She could feel Issei turn the mask and put it on. As Issei started seeing images and her memories, she starting images of him and his memories too. She saw him get his heart ripped to pieces by the group from before. Saw him fight fallen, devils, Loki and others, she felt his pain too. The pain from light spears, all his fights but none came close to his heartache. She was screaming as she saw Issei turning into the creature she was before. A mask started to manifest on her face as well until it suddenly fell off, she couldn't see Issei anymore but his presence changed.
Woman: *huff huff huff* WHAT JUST HAPPENED TO YOU?
She saw that there was something else happening to him besides the mask trying to take over. She sat there contemplating what was really happening to him to cause his presence to become very different. She felt apathy within Issei. After an hour or so she felt him put on the mask once more, she saw more memories of his and finally heard his name just before she lost the connection.
Woman: Issei...that's the name of my soulmate. I hope you can find me, I don't know where I am. I'm scared.