Keiko
As Keiko stood in front of the Nightmare, sword outstretched, she decided that if she wanted to have any chance at survival, she needed to do this perfectly. There was no ambiguity in this fight. Keiko was much slower than her opponent, and, although she knew she was somewhat skilled with her sword, the Nightmare was certainly better.
That meant that victory was just not a possibility. All she aimed for was to give Ash enough time to heal Yumi. All she could do was hope that, if she was still alive by the time the ability expired, Yumi would be back in fighting shape.
Of course, she also couldn't use her Spirit Eye as a crutch either, as this Nightmare was somehow able to cheat it. Therefore, without her Spirit Eye, without the same level of skills, without much mana either as she'd used the majority of it to cast this ability, Keiko had to survive.
Level 36
MP: 20/150