Ah. Gentiana. She came to them to engage Noct in the trial of Ramuh. No wonder Noct thinks he had her blessing ever since Tenebrae. She was there when the Prince was injured and tied to a wheelchair.
Ignis doesn't curse Leviathan's name, but he doesn't give her his blessings either. Her stubbornness, even after so many pleas, got Noct to the brink of death. He can't be grateful to her for that.

"Rest now," Ignis says, putting the cups on the empty seat next to him. Perhaps there aren't many things Noct wants to dream about right now but, "Carbuncle will watch over you," Ignis adds with a small smile.

As will he.