Ignis Recognizes Sania Scenes
It started at Chapter 3 Sidequest redfrogs.
And the rest of the sidequests.
Afterward, Ignis Scientia ponders where he has heard of her, and recognizes her surname, as Sania's parents are likewise renowned scientists. He does seems to care about her too. If you ponder someone over and over again without even knowing it. They care about that person. Whether you believe it or not. Facts don't care about your feelings.
Link: Rainbow frogs - https://youtu.be/gBsNDITdGzs
Link: Yellow frogs - https://youtu.be/k9P9xa_BRVo