The most useful unit upgrade.

I’ll say right away that I didn’t like the poll; I think it would have been better to create a poll asking which of the 7th-level creature upgrades is most useful for a specific Castle. Regarding Gremlins and Mages, they said that they aren’t that important. I disagree. Gremlins definitely need to be upgraded; if not from the first day of the game, then certainly from the second. It’s a very useful upgrade in the early stages. The combination of upgraded Gremlins, Gargoyles, and the Mage’s magic allows you to defeat units with almost no losses. Next, Mage -> Archmage. I generally don’t deploy them on the battlefield against archers unless they are well-protected because the Magic Fist isn’t very effective, and if they are shot at, they will die too quickly. Therefore, I’m all for Archmages with Fireball and three hit points! The Titan, even in its unupgraded form, is quite effective; it’s mainly needed to kill annoying units (like Vampires, for example). Rakshasas, Djinns, and Golems – I consider these to be the worst upgrades at the Academy, and they are also quite expensive! Furies, Dryads, Skeletons, Angels, Demonesses – these are specific to each Castle.