Thanks for the chapter!
Looks like the MC has won over Yukari's heart. She's definitely going to be very devoted to him once she gets her thoughts in order. Speaking of which, will be interesting to see if this is one of the stories where dark elves have a very strong libido and stamina and if MC can keep up with her without dropping. XD Although if it does happen it'll likely be one of those she comes into the room expressing her desire, he'll accept, and then it'll be the morning after with both of them in bed with the covers pulled up so nothing will be shown from either of them.
Come to think of it, how much history of the game does he remember, and at what part of it are they in? Not likely to remember every little thing, but should recall and prepare for big events like a monster stampede somewhere or a new Demon Lord rising up and trying to destroy humanity while bullying/killing any demons who protest or aren't into violence and murder.
LN explains it better but due to her contract she can't attack a human being. However, it seems the force that enforces obedience is restricted to a bunch of listed things labeled as an attack that didn't include headbutting. Hence by having Yukari headbutt him the MC used one of the dirty ways of breaking the contract without penalty. Likely due to the paradox of her attacking her master using an attack that's not restricted but should have been. One of those bugs from the game that players discover and can abuse that hasn't been corrected by the developers. Like the bug from Vampire:Bloodlines where can assign points, go back to page where pick clan, and then go back to point assign page where have points can assign with same number of points can assign but with all previous assigned points still assigned. So if assigned points to max out strength and used trick would still have points to assign but strength would still be maxed out.