Im ready to be wrong here, but with the increased power of two and three drop creatures, five mana removal is worse than it used to be
As far as the rest of our lessons, Boomerang Basics, Firebending Lesson and Iroh's Demonstration are all reasonable removal spells, with Iroh's Demonstration likely the weakest of the bunch, but still fine thanks to its flexibility of wiping out a board of X/1s or killing one larger creature
Whenever looking for a mechanic, we often look for what existing mechanic fills the shape we need
there are five core rarity tiers in total
This is also one of the best legends for Duel Commander and 1-on-1 matches thanks to how quickly it trims away an opponents resources, leaving them starved for options while you keep gaining card advantage
The sheer variety of build paths and the unique style of a card that needs to be in combat but doesn't care about damage makes Fire Lord Azula the most interesting commander in the entire set