When Axel unlocked the Infernal Domain ability, the system had explained to him that activating it would send the host (him) into a space where he held absolute power and could also trap individuals conceivably weaker than him.
Diana was anything but weak, and she was sure to be ten times stronger than Axel in terms of speed, raw strength, combat skills, and prowess in general. Thus, when Axel activated the Infernal Domain, everyone in the room, including a certain second-year student who had been hiding behind the portal door, was transported to Axel's personal space.
All except Diana.
<[You are now in your Infernal Domain; your power over this domain is absolute]>
Axel suddenly felt a strange sensation wash over him, specifically around the area where Diana's sword had gone through. His wounds sealed, and the blood stopped pouring out.
"It worked."
