This is according to a report from Variety in which Blizzard North programmer Johnathan Morin found himself with some free time after finishing Diablo 2, and was on the hunt for a new project. Pokemon was a big thing back then (and still is today) and so the idea of doing something similar, except with Diablo characters, sounded like it could be a fun idea.
According to Morin, “Look at how successful ‘Pokemon’ is. How can we do something similar? There weren’t a lot of games on the Game Boy like that at the time. We could bring the ‘Diablo’ universe to Nintendo. I think it would have done awesome.” However the project never got too far because while in the middle of planning it, Blizzard North and Blizzard South merged into a single studio, and Vivendi (who was Blizzard’s parent company back then) wasn’t sold on the idea and canned it.
Morin says, “Blizzard South came in and they were asking what everybody was working on. Oh yeah, I’m working on this Game Boy game! … They had no idea. They’re like nope, sorry, we’re going to cancel that.” No doubt it sounded like an interesting idea, but given how fans reacted to Diablo Immortal, we’re not sure if a Pokemon-like Diablo would have fared any better, or would it?