The drill slots feature allows the three highest-level heroes to be automatically assigned as instructors, providing the opportunity to use other heroes in the drill slots to level them up.

When heroes are placed in the drill slots, their level gradually increases until it reaches the level of the lowest-level instructor.

Important Notes:
Heroes can only be placed in the drill slots if they are inside the city.
-If a hero leaves the drill slots, the slots enter a cooldown period of 24 hours.
-Upgrading the Halls of Heroes increases the number of available drill slots.