Unit Promotion in Fire Emblem Engage is another way to label the mechanic of changing a character's Base Class to an Advanced Class. Advanced Classes serve as the superior and more specialized forms of Classes in the game. For instance, if players wanted to capitalize on Etie's capabilities as a ranged DPS unit, they could promote her from the Base Archer to the Advanced Sniper. As a result, her Class Skill would also change into No Distractions, granting a boost in Critical Damage when attacking an opponent unable to counterattack. However, the jump from Archer to Sniper is not free and requires multiple conditions to be met before the Promotion is performed.
To promote a character unit in Fire Emblem Engage, players must first understand how to get a Promotional Item known as the Master Seal. Those familiar with past titles in the series should already understand how this item works. However, for newcomers, the Master Seal works as a "key" for unlocking a unit's Advanced Class after other prerequisites have been met. For example, if players want Etie to become a Sniper from an Archer, they must ensure she reaches Level 10 and has achieved an S-Rank Bow Proficiency.
How Class Promotion Works in Fire Emblem Engage
The Master Seal and level requirement of 10+ will always be constant across all Advanced Classes, excluding the exceptions of Dancer and Thief. Nonetheless, the Weapon Proficiency will differ depending on the Class into which players are promoting a unit in Fire Emblem Engage. Still, just because a character reached Level 10 does not mean players must unlock a new Class straightaway. For example, the YouTube channel The Game Looters suggests that Divine Dragons wait until their characters attain Level 15 or the max of 20. This strategy enables players to get the most out of their units' Base Classes before the Promotion, yet there is nothing to lose when unlocking an Advanced Class.
For those curious regarding Master Seal procurement for unit Promotions in Fire Emblem Engage, these high-end Promotional Items can be earned during specific chapters. They also become available for purchase after the transition from Chapters 8 to 9. The stock is initially limited, but the restriction is lifted after Chapter 18, letting players customize their units' Advanced Classes more freely in the late-game. For example, suppose Divine Dragons would like to reset the Advanced Class of a specific character and set them back to their Base Class. In that case, they can do so by using a Second Seal.
Source: YouTube/The Game Looters