Jeth Arck Piper.
He was Ivor Osan's spare identity, acting as a renowned member of the Escalon Guild.
He had joined Sebastian's company along with his squad to confront Isen's forces. Piper's inclusion was an obvious choice, given his reputation as the "Baron's Bane" for his previous success in thwarting Isen Osan's advances on a different battlefield. However, little did his comrades know that Piper had downplayed his achievements.
In their last encounter, Piper had defeated Isen outright, yet he chose to let him escape. Despite sustaining critical injuries himself and witnessing his team members getting hurt, Isen fared far worse. If Piper had pursued his advantage, Isen would have been utterly defeated.