The Training Tower is a feature in Fire Emblem Heroes
The Training Tower is a training ground for the player's Heroes. Players can choose from 11 different strata, each comprised of various enemy units. The higher the stratum is, the higher level the units are and the more Stamina is expended to start it. The Tenth Stratum has particularly challenging units who may have unusual skills equipped. Each Stratum also changes anytime a battle is complete, even if it is a Story Mode chapter, Special Map, or an Arena Duel.
Unlike Story Mode, EXP does not scale if the player has completed a stratum before. Completing a Stratum award Crystals upon the first completion of a Stratum daily and will always award Badges. The Badge color given depends on the day of the week.