clarification on kaeya's behavior in the caribert quest
seen a surprising amount of people taking kaeya's words at face value so i'd like to point out a very important detail that has been easily overlooked
i don't have any video clips of this and the official soundbite unfortunately cuts off abruptly so you'll have to trust me on this or just do the quest again yourself lol but
right here, in the very beginning of the conversation with kaeya, kaeya suddenly goes quiet and contemplative. if you pause long enough and NOT immediately skip ahead, you can actually HEAR footsteps approaching and kaeya going "hm?". and THIS is the moment when kaeya starts talking about his past. this means he knew dainsleif was there from the very beginning.
he then loudly proclaims that he knows NOTHING about khaenriah and that his dad probably had GOOD intentions (directly contradicting his character story) making himself purposely look naive and harmless in front of dainsleif so he could lure him out and get answers out of him or maybe he was just tired of this guy following him around. though to his credit dainsleif himself didn't seem totally convinced of his act
as to why kaeya knew it was dainsleif just by his footsteps, there could be several reasons: 1) he saw dainsleif in sumeru beforehand and just guessed it was him, 2) he can sense the abyssal corruption inside of him and because he already spotted dainsleif before in mondstadt, could tell it belonged to him, 3) he's an all according to keikaku character and we're not supposed to think any deeper of it
tl;dr sometimes characters who are known to lie, lie
(Sorry to interject. I hope it's ok to add something. I probably look like an ass "well actualling" this post but there's something about the footsteps. orz)
You can actually hear footsteps all the way through the conversation, not just during his pause. Importantly you can also hear them once Dain has already joined them:
So I think they are a general background sound effect caused by other NPCs walking around and you can just hear it more clearly when nobody is talking, like during Kaeya's pause (but also during Dain's pause).
I do believe Kaeya is pausing because he takes Dain's presence into account and calculates what to say but the footsteps might just be a coincidence caused by Port Ormos' general sound design.
(I think the issue around his father's intentions is more nebulous than just good/bad tbh, esp. with the English localization retroactively changing Kaeya's line to
"Maybe my father left me in the peaceful land of Mondstadt for no other reason than simply to keep me alive... Kaeya: As well as ensuring that I'd be safely cut off from certain things..."
To me that intention sounds a lot more neutral/ambiguous. He might want to keep Kaeya alive to ensure he can play his part in a later plan. Perhaps child Kaeya used to live in an environment that he might not have survived in till adulthood, endangering whatever his father was up to. At the same time I don't think it's unreasonable that as a father he could simultanously also want to protect his child from certain harm. So his father having ulterior motives while also caring about his son's well-being aren't necessary mutually exclusive to me.)