Rune's eyes were fixed on Grace as he spoke the words - "I can't give you any promises, but this one. I will protect you over my life. And as long as I'm one of you, I'll follow your orders and do my best to protect the rest of the team."
His gaze shifted to Davian before he continued, "You know that I'm trained for fighting those monsters and you all will need to fight them sooner or later. Keeping me in your team will give an advantage over them. I know their weaknesses, their kinds, their secrets, and the ways to kill them. And trust me, there are some kinds of these monsters out there whom you can't kill with your Mortal weapons. You need me."
He was right. They did need him if they wanted to find a quicker way to handle the monsters. He could be their biggest advantage against them.