I may not be the best at dealing with people, but I feel telling someone dealing with an insanity curse that's destroying her self-worth at every opportunity that she's "out of her mind" may not be the best approach?
Not to mention... the Disciples' plot is an end of the world scenario, here. It was never just about Kohaku.
[X] Start off firmly, but kindly. "Kohaku? You. Are. Not. A burden. And taking off again will make everyone worry, and make intercepting the remaining Disciples almost impossible. Your dad... Grandma says the curse he put on you, he can use when nearby to track you down -- and we can use that to catch him. We can stop his entire scheme in one go, prevent the sort of disaster from occurring that happened to Kazuya's world. This sort of thing is exactly what my family has dealt with for generations... and is
quite good at, from the stories I heard tonight. I don't know if I believe in fate, but I do believe in luck... and you lucked into running into
exactly the people you need to help you stop all of this in its tracks! Not to mention, two old friends who missed you, so much." Smile fondly at her, on this last sentence.
-[X] Regardless of that, do you seriously expect me to leave you out to dry now? After all this? Knowing what I know now, Kohaku, I'm not letting you go. Not until I've set things straight. For you, and for myself."
-[X] Grab onto her hand with both of yours. Make sure she's looking at you in the eyes. "Until we've seen this through to the end, I want you at my side. I want to be able to see you smile, laugh, cry, and rage with the rest of us! I don't care at how difficult the trials are, nor at how cruel the world may be! Until I can see you and everyone else free and happy, I'll fight. No matter what."
--[X] Realize how much that sounds like a marriage proposal. Try not to blush. Blush a lot. Don't take it back.
Last bit may be a bit anime-filtered-Japanese-culture, but oh well, chop it off if you don't like it.
