>>2376522I'd say it's because of the chemistry and implications between Gladio and Noctis, which are then transferred to their fathers who have the exact same roles. Their positions as King and Shield mean they've been together for almost their entire lives, and obviously in Kingsglaive Clarus stands beside Regis until the very end even though he knows what's going to happen. They're what Gladio and Noct could have been if Noctis had lived long enough.
There isn't much in the way of them interacting, so it's just fandom filling in for them. I rather like it, though. I think it's a pretty cute pairing, though I don't seek it out that much.
