Pretty sure they are low key implying Edmunt for Sera and/or the ominous child we saw for like a chapter earlier for Elodie
I think the antagonism between the prince and Edmunt will increase when Sera is finally exposed (also showing elodie that sera can have a romance that is good and healthy). And the children have the whole holy healing vs cursed death dichotomy going on. Those are my thoughts at least :/