Scepter of Fire campaign: Even though it can't grow into a diffrent class, Krawg the gryphon has "intellegent" trait. Why is that? Because Krawg is a talking gryphon.
Descent into Darkness campaign: Just who is responsible for Malin Keshar's fall to darkness? We could blame Malin himself, or Darken Volk, but we forget one important character here: the Ghost-line unit that has dialogue several times throughout the campaign. Each time it appears, it offers its advice to Malin, usually nudging him towards some nasty things (attacking the people of his hometown, betraying Darken Volk, becoming a Lich). Now, because it is always the most powerful Ghost-unit, it will likely be one of the very first ghosts that Malin recruited in the third mission, which go rogue several times during this mission and, in-universe, come from the goblins Malin killed in the second. This ghost has been playing the long game: slowly feeding Malin's self-destructive impulses, in the hopes that one day, someone would kill him, set it free, and avenge its death. One of the most powerful liches of all time was brought down low by an undead goblin.
The final mission of this campaign also qualifies, though if the forums are anything to go by it's a YMMV situation. After slowly succumbing to the dark influence of necromantic magic, corrupting his morals, and eventually embracing his exile Malin ends his(un)life in a mountain lair surrounded by a powerful undead army including a skeletal dragon of all things and guarding a powerful tome of dark secrets. Every year he's assaulted by some hero he never bothers to learn the name of for the collateral damage his army caused them. The mission literally repeats over and over, randomizing the enemy. At some point it dawns on you: you're the final boss at the end of their campaign. You may have started out trying to be a hero but you've become a villain instead.
