Rarity

A 4★ Lilina; her rarity is shown above her epithet, Delightful Noble.

Rarity is an aspect of all units appearing in Fire Emblem Heroes. It denotes both their, as the name suggests, rarity, and an approximation of how powerful the unit is. A unit's rarity is represented by a number of ★ on their stat screen and elsewhere during gameplay.

Overview

The different color borders given to characters of different rarity.

A unit's rarity, despite what its name may imply to some, is specific to individual units, and not every instance of the character. A unit's rarity can value from 1★ to up to 5★. A 5★ unit is going to be much more powerful than a 1★ unit at the same level, even if the two units are the same character.

The exact calculations for these statistical differences are currently unknown. Several characters also have specific skills that can only be unlocked once they meet the ★ requirement (often 5★) as well.

A character's rarity also alters several graphical elements, such as the border around their portrait. 5★ units will also have golden sparkles on their map icon and in their stat screen. 4★ units have silver sparkles in their stat screen, but not their map icon.

Generic enemies can also have rarity values. Generic enemies of higher rarity are seen in higher difficulties, and are more powerful than their less-rare brethren, being given both higher stats and more powerful skills.

Rarity and summoning

A 4★ Nino on the summoning screen.

The lowest possible rarity of characters obtained through summoning is 3★. 1★ and 2★ units are generally obtained from special maps that give out characters. Some characters can be summoned at any rarity between 3★ and 5★, while some characters, such as Lucina, can only be summoned at 5★ rarity, making them quite rare. Lower rarity versions of characters that can only be summoned as 5★ only appear as enemies.

A unit's rarity is shown immediately on the summoning screen under their map icon, making their rarity one of the first things known to the player. Aside from being stronger, units summoned at higher rarities also benefit from having more skills unlocked from the start. For example, a Henry summoned at 3★ rarity will start with only the Ruin weapon skill, while one summoned at 4★ rarity will start with the more powerful Rauðrraven weapon skill as well as the special skill Glowing Ember.

Unlock Potential

Attempting to unlock Lilina's potential, though the Hero Feather requirement is not yet met.

Through a process known as Unlocking Potential (Japanese: 覚醒 Awakening), a unit's rarity can be increased by one ★ at a time by spending both Badges and Hero Feathers. While originally a unit's rarity could only be increased at level 20 or above, the version 2.9.0 update removed the level requirement. Upgrading a character from 1★ to 2★ is relatively trivial, though upgrading a character from 4★ to 5★ is quite expensive. When a unit's rarity is increased, their level, stats, and merges will be reset to their base values for a unit of that rarity, while their SP, learned skills, and Dragonflower enhancements are retained.

The Badge used must match that unit's color. Red units use Scarlet Badges, blue units use Azure Badges, green units use Verdant Badges, and gray units use Transparent Badges.

Unlocking costs
★ increase	Badges needed	Hero Feathers needed
1★ to 2★	/// 5	20
2★ to 3★	/// 10	200
3★ to 4★	/// 20	2000
4★ to 5★	/// 20	20000

Gallery

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  A 4★ Nino on the summoning screen.

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  A 4★ Lilina, her rarity is shown above her title, Delightful Noble.

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  Attempting to unlock Lilina's potential, though the Hero Feather requirement is not yet met.

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  Sakura after having her potential unlocked.