Nathan bit down on the inside of his cheek to keep from speaking at the chorused pronouncement, glad of Cordelia's correction, as he knew she likely ranked far above him in terms of importance of opinion, even if their opinions still ranked below Peter's.
Having been addressed directly, however, his personal space very invaded in the process, Nathan paused a moment before deciding to speak. "Yes, I do," he admitted, his gaze steady. "And while that's part of the reason I'm here, that isn't the reason you need to listen to my brother - the Champion." Mentally, he was running through key warnings from others and from years of experience, knowing that his words needed to be careful, especially now. Use titles they seemed to associate with people, it would avoid confusion. Address the issue in terms of benefit to the mission, not emotional pleas. Attempt to shut up sooner rather than later.
"The Seer is right," he said, not looking at Cordelia, only the being in front of him. "The Champion doesn't stand alone. If worked like that before this, then that's how it worked. But that is not how the current Champion does what he is here to do. There are many that play an important role in his life. If a part of that, a needed part, is removed, it will affect the Champion and the mission. Mantis is a needed part."
He could say more, easily. But he knew they needed to listen to Peter and he recognized if he didn't stop there, he might need to have Peter clamp his mouth shut.