Hm. Taisan does not need to breathe, however we have not thoroughly tested the distance we can be separated with him in a physical form. The length and breadth of the Bastion is as far as we have attempted.

Now might not be a bad opportunity. If he dissipates, he can return and tell me immediately.

However, I do not know of anyone else that does not need oxygen. I could write spells to purify the air around a person...though my arts are restricted. To what degree I cannot know without trial and error.

I dislike risking others for experimentation when there are so few of us.