Sounds like a balloon note.

Most typical in a 2nd mortgage would be to set it up with a 30 year payment, but having the remaining balance due in full after 5, 10 or 15 years.

Since they demand the balance before the payments would actually pay the loan off, that would fit the “demand feature”.

It could be a couple different things - A demand could be the payoff or it could be when the loan comes due - for example if you have a fixed rate loan 30/15 that would imply that your payment is made like you have 30 years to pay the loan off but really at the 15th year on the day the loan recorded it will come due. at that point you need to refi or pay it off

Hope that helps !!

- it would be a lot easier to answer your question if i knew the context of how “demand” was used on the note.