In Fire Emblem: Three Houses, unlocking powerful class-specific skills isn’t as simple as hitting a certain level anymore. Class mastery is the name of the game, and while it may initially feel like a long and tedious grind, it doesn’t have to be. With the right knowledge and a few clever setups, you can turn your units into efficient class-maxing machines. This guide walks you through how class mastery works and how to use the system to your full advantage.

How Class Mastery Works: The Basics

Each time a unit enters combat, whether they deal damage, take damage, or even just dodge an attack, they gain 2 class experience points. Exceptions include certain AoE attacks from demonic beasts and rallying actions, which don’t count. However, healing and dancing do grant 2 class experience points per use, making them viable grinding options—up to a point. Eventually, the game will cut off class experience gains for spamming a single action like dancing, forcing some creativity in your approach.

Every class requires a different amount of experience to master:

• Commoner / Noble: 20 EXP
• Beginner: 60 EXP
• Intermediate: 100 EXP
• Advanced: 150 EXP
• Master: 240 EXP

Upon mastery, your unit unlocks a special ability or combat art tied to that class, which can be carried over to other classes and even future playthroughs through New Game+ if you spend Renown. For example, Brigands grant the coveted Death Blow (Strength +6 on initiation), while Mercenaries give Vantage. Not all rewards are equal, however—Master classes typically offer “Defiant” skills that activate under 25% HP, making them riskier to use consistently.

One standout exception is Lysithea, who gains double the class experience per combat due to her personal skill, Mastermind. This makes her ideal for quick mastery grinding and a centerpiece in any strategy that aims for fast progression.

Boosting Class EXP with the Knowledge Gem

The Knowledge Gem is a must-have tool for class grinding. It doubles both skill and class experience gained per encounter. With it, most units gain 4 class EXP per combat (6 for Lysithea). You can acquire this item in two key places:

• A chest during the Red Canyon paralogue
• In Chapter 11, by completing all secondary objectives (not allowing any enemy to escape)

Just be aware that on maps with infinite reinforcements, these reinforcements will only yield 1 class EXP instead of 2, limiting your farming potential. This appears to be an intentional balance by the developers.

Efficient Class Mastery Strategies

Let’s get into the good stuff—how to exploit the system for fast mastery.

1. The Archer Trap Method

Archers are ideal enemies for safe, repetitive combat. Equip a melee weapon (no 1-2 range) so your unit can’t counter, and let the Archer shoot each turn. You gain EXP every time they fire, even if they miss. Make sure no other allies are in range to tempt the AI away from your chosen unit. Forest tiles lower hit rates and help with survival.

To make this setup even safer:

• Box the archer in using your own units.
• Place a healer next to the unit being hit.
• Use physic spells to heal from a distance if space is tight.

2. Healing and Faith Magic Support

Healing grants class EXP as well, and long-range faith spells like Physic are invaluable for keeping units topped off without interrupting the trap. Several units can learn it, including Linhardt, Mercedes, Dorothea, Ashe, Marianne, and more. For group healing, Fortify—learned by Mercedes and Flayn—provides even more efficient EXP.

3. Use Warp and Rescue for Seamless Swaps

Once a unit masters their class, you’ll want to rotate in a new one. Spells like Rescue (Flayn, Bernadetta) and Warp(Linhardt, Lysithea, Manuela) let you quickly move units in and out of range. This prevents downtime and keeps the grinding engine running smoothly.

4. Trapped Enemy and Demonic Beast Setups

Sometimes the map layout or enemy behavior traps a foe in place. Use this to your advantage. Against demonic beasts, be aware that their AoE attacks don’t grant class EXP, but regular attacks do. Since they only attack normally every other turn, grinding against them is slower but still viable. Bonus: they often stand on healing tiles, which helps maintain the loop.

5. Boss Units Who Can’t Move

Non-mobile boss enemies are another excellent target. They can’t reposition or chase your team, allowing you to safely rotate in weak attackers. Their healing tiles let you keep the fight going indefinitely—as long as you manage damage output to avoid accidental kills. Use broken or rusted weapons to reduce your hit and crit chance, especially if using strong units. Misses still give you class EXP, so don’t worry if attacks fail.

6. The Class Maxing Machine

This is the gold standard. Box in an archer with four units so they can’t escape. Then alternate units inside their range each turn, passing around a Knowledge Gem. You’ll have complete control over who gains EXP. Even better, if your healer and defender each hold a Knowledge Gem, you double the grinding potential. Just be careful: once the enemy’s weapon breaks, they’ll start missing more and you may lose the ability to heal.

Other Key Reminders

• Battles are capped at 100 turns. Don’t overstay and miss the chance to end the fight.
• Divine Pulse cannot be used after the final enemy is defeated.
• Class EXP farming does not yield much weapon skill or character level EXP—don’t expect to train everything at once.
• Anyone standing adjacent to Byleth can access the convoy to swap in rusted or broken weapons as needed.

Adjutants: Double the Output

Lastly, don’t forget to assign adjutants. The lead unit gains class EXP, but so does the adjutant, making this a two-for-one system. The Knowledge Gem doesn’t help the adjutant unless they’re wearing it themselves—but if you have two gems, this becomes a potent combo.

Conclusion: Efficiency is King

With these techniques, class mastery becomes far more manageable—and even satisfying. By using terrain, enemy behavior, utility spells, and equipment cleverly, you can build up your roster with powerful abilities that transfer well into future battles and playthroughs. You’ll spend fewer resources, save time, and walk into each fight with confidence knowing your units are performing at their peak.

Fire Emblem is a game of strategy, and class mastery is just another arena where your planning pays off. Now get out there, and start maxing those classes.