What, exactly, are they promising to do in terms of promotion that is worth leaving you with almost nothing? Unless you are partnering with one of the absolute top-selling instructors on Udemy and they are working closely with you on the production process to meet their standards, I can't see this working to your benefit.
You'll end up making less than a dollar per enrollment, even though you're doing all of the work. Much less. Remember Udemy takes 67% of your revenue, app stores can take another 30%, taxes another 15% in some countries... and then you'll only get 25% of whatever is left over? Keep in mind you're typically only starting from a sale price of $5-$12; people do not buy courses at their list price.
Who is responsible for managing Q&A and updating the course over time? Will this be worth your time going forward?
AND they want you to hand over copyright so they can monetize your content in other ways and give you nothing? If I were you, I'd send the details to policy@udemy.com as I question if they are even in compliance with Udemy's co-instructor policies. They might at least let you know if the firm you are dealing with is reputable or not.
It's possible you're dealing with someone legitimate, but I'm afraid it's more likely you have crossed paths with one of the many shady characters trying to exploit new Udemy instructors.
