Ryan Grimshaw is a boy born at a noble house but someone who was raised by a hunter after the age of six and was taught everything about a very basic yet necessary concept.
Survival.
Being pushed into the wilderness at such a young age taught him several things, but the most important part he learned from those days was how to exploit even the slightest opportunity at a disadvantageous position.
The moment he knew who his opponent was, Ryan knew he wouldn't be able to win against her through normal means. And the way she began her onslaught, made it obvious that unless he exploited the only ace up his sleeve, he wouldn't be able to win.
As such, he went for the win and paralyzed the girl.
However...maybe he underestimated the S-rank warrior a little, and in the end, he was labeled as the loser—just as everyone expected.