You cannot grow stronger unless you learn from your enemies. And that's exactly what Austin did when he realized the difference between him and his enemy.
He had more than one way to subdue the demon, asking Sebastian would have been the easiest. However, he was striving for a stronger self, wanting to become someone who could stand beside Valere and face the dangers that would be threatening the world in the near future.
As such, the most important thing, he needed to do was,
Learn.
[Skill 'Adapt' is in use!]
[Time remaining: 30 seconds.]
Austin shot toward the demon, his speed exceeding Kalwar's expectations, as it hurriedly raised its claw to parry the attack. However,
*SQUELCH*
It was stabbed from behind, the target in front dissolving into a mist.
Kalwar's eyes widened as it shakily muttered, "H-How....c-can you use my s-skill...."