I've noticed that Kain, along with all the other shopkeepers, says "I see you have a discount card! I'll give you a discounted price of xxxx sP!" when buying with a discount card. But Kain can't see.

I know it's minor nitpicking, but it matters to some people, like me. Is it even possible to change it to something like "I sense you have a discount card!" or "Thanks for telling me you have a discount card!" I know all NPCs say it, so it's probably in the coding.

SEE verb (used with object), saw, seen, seeing. (...) 5. to perceive (things) mentally; discern; understand:

Not that I disagree with this, it's something very small and can't harm anyone, but using "see" with him is also not wrong! :)

Kain should make more seeing/eye puns imo.