It has to be someone, with the way things are now. Marshal Leonis is hardly in any fit state, he and Libertus both will no doubt be occupied directing the rest of the Kingsglaive and coordinating rebuilding efforts of their own.

[A pause, in which Ignis took a slow breath. He felt far older than thirty-two, and it was beginning to show in his sheer exhaustion.]

...It would be wrong, to stand aside now. I know they must feel the same. We are the Glaives of the Chosen King, and Noctis would never have stood back from a world in need of aid. The three of us can ask no less of ourselves.