You're looking for this one You can log in to battle net and go to
https://us.battle.net/account/management/
(the screenshoteu or us shouldn't matter)
Click on Diablo II, you'll be taken to the page with the key(screenshot is in Italian, but you should get where to lookthat shouldn't be a problem):
You're looking for this one (the screenshot is in Italian, but you should get where to look):
You can log in to battle net and go to
https://us.battle.net/account/management/
(eu or us shouldn't matter)
Click on Diablo II, you'll be taken to the page with the key(screenshot is in Italian, but that shouldn't be a problem):
