Character relationships?

[Shiro--Tsubasa]

I can see it for maybe side characters that don't have strong story relevance, but not from the scions. Maybe that one npc that you like the design of at the market place. You can start up a social link like quest chain where you help them do different things and build up affinity with them eventually leading to a higher level of relationship. Or create npcs specifically for this.

It won't work on scions or important npcs due to them possibly dying n stuff. It would make for interesting dialogue changes though. It would just be to limited.

other things that could be incorporated through this
companion system - allow you to take the npc with you to fight alongside one another outside of dungeons, raids, etc.
a quest (daily?) - where you do things with your partner whether it is fighting monsters, crafting, or gathering, etc.