Jack's eyes widened in relief when he heard Finn's words. He forgot that a king of war was with them; Klaus's massacre took control of his brain, and he forgot a powerful figure like Finn was with them.
Most of his merits on the battlefield were given to him by Finn, and yet Finn was still ranked as a fourth star king of war.
Finn didn't contribute anything like giving out information or resources; he was ranked as a fourth star king of war mainly on his combat prowess; rumors have it that he could have been ranked as a fifth or sixth star king of war if he had taken all the glory of his work.
Jack's heart finally calmed down. Klaus might not be a normal private, but surely he wouldn't be comparable to a king of war, even if he was; Finn was a fourth-star king of war, even comparable to a sixth star, so Klaus wouldn't be able to scratch him let alone defeat him.
"King of war Finn, I want you to cut this bastard down limbs by limbs"