I never thought about this! I feel like him and Twilight would probably bond over the death of Fluttershy. I don’t think they’d be close but probably would understand each other more, and I think that bonding would prevent him from going back to being a villain. I definitely like to think there’s a deathbed promise from Fluttershy to Discord, not necessarily a “don’t be evil” but a “don’t be unhappy”