List of stats
Rarity is feature unique to units, whether they are playable characters or utility units. The rarity rank is shown below the unit, at the Unit detail screen, by using a number of stars ranging from one (★) to six (★★★★★★), with the latter being the maximum they can attain. Unfilled stars show the unit's potential to go higher.
Rarity, in playable characters, roughly determines how good they are in comparison to others, due to their higher relative stats and their wider range of abilities. Units have different base rarities on the type of summon they are: Standard Summons' base Rarity may be 1-2★, while Rare Summons' base Rarity may be 3-5★. Units have different base and maximum ranks, even if they are the same type of summon.
There are several types of level. The first, is the character's "experience" level, an accumulation of points earned through battle. Once a unit gains enough experience, they will level up. The maximum level units can go will depend on their Rarity, and once they reach that maximum, the unit may be awakened to the next rank (if applicable). Once awakened, the unit will start back at level 1, only this time with higher relative stats, higher maximum levels, and more abilities to learn.
The HP stat shows how much health a character has left. Once it reaches zero, a character reaches KO'd status.
The MP is a measure of how many abilities which require MP (whether magic or special) can be cast.