Obsidian.

The aura exuded by their comrade took Sitta and Trenta by surprise. The fear they felt was now directed at Zero Five instead of the crimson queen, so much so that the thought of teleporting away crossed their minds.

The aura grew so thick they could no longer see her form. The red lightning stopped raining, but Thor was still, keeping her distance and not attacking like she usually does. It was as if she was waiting for whatever was happening to end, and it didn't take long before they reached that point.

Nino had said that the ponytailed Valkyrie was the only one strong enough to win against the crimson haired queen, but she refused to tell them why she thought that. Using her ability to see the future she must've seen how Five would do it, but her refusal to give them the method led to the conclusion that knowing about it might result in failure somehow.

Sitta didn't understand why that was the case back then, but now she had a vague idea.