Fire Emblem Engage throws multiple fantastic classes at you, most of which are locked to the specific Lord characters you'll encounter. While these are extremely powerful classes, some of the generic ones shine through more for your non-Lord units.
Classes are a staple of Fire Emblem games, and it's always the case that not all of them are ever born equally. Some are just better than others, reducing the utility of many classes unless you want to change things up on a playthrough.
Spoiler alert: we will discuss characters who join you later in the game after certain story events. If you don't want to know who some of these are, you should turn away now.
12 Seadall - Dancer
It wouldn't be Fire Emblem without a Dancer class. This unique job is for Seadall, and it's one of the special classes in the game. Dancing lets you give one of your units another turn after acting. Dancers in Fire Emblem typically can't take a few hits without dying.
This has been slightly rectified in Engage, with Seadall joining your party with ten points in Defence. This goes a long way in increasing his usefulness and survivability, especially when combined with Seadall's Personal Skill that restores adjacent allies' HP.
11 Mauvier - Royal Knight
Mauvier is one of the characters who you first fight as an enemy. He eventually joins your team after a later-game story beat, which is a regular occurrence in Fire Emblem Engage. He joins you as a Royal Knight, one of the better advanced mounted units. The Royal Knight class covers so many bases in Fire Emblem Engage.
They can equip Lances and Staves, giving you access to healing and utility staves like Physic and Rewarp. Mauvier has incredible stats all around, with fantastic Resistance and Defence for a mounted unit. Mauvier joins late in the game and is powerful enough to hold his own.
10 Merrin - Wolf Knight
Wolf Knights are exactly what you might expect. Merrin joins as this class by default, and it has incredible speed and damage as a knife-wielding unit. Merrin's abilities as a Wolf Knight are wonderful, boasting high mobility, and using daggers for ranged attacks and swords if she needs to.
There's plenty more versatility in Engage than, for example, Three Houses, letting your units shine in multiple roles and cover more bases than before. Merrin being in this class by default does a lot of harm if you're trying to level Yunaka to promote into a Wolf Knight since she does everything so much better.
9 Alear - Divine Dragon
As you might expect, Alear being the main Lord and Avatar of Fire Emblem Engage, they are a strong unit by default. Alear's exclusive promoted class, the Divine Dragon, is one of the best in the game.
Divine Dragon has some of the best growth rates across the board, with an excellent spread for Defence and Resistance. It should be no surprise that Alear is best suited for a sword-using class, but feel free to put them into any class you want.
8 Goldmary - Hero
Goldmary is the first Hero unit to join you, and she might be your first Hero full stop if you've not promoted any of your sword fighters to this class. Goldmary herself is sassy and arrogant, which is fully earned when you see how badass she is.
Hero classes can use Swords and Spears or Swords and Axes, but it depends on which version of the Hero you promote into. Goldmary has strong stats and joins you later in the game. She's another one of your previous enemies joining your ranks.
7 Alcryst - Tireur D'Elite
Alcryst is one of the better bow users you'll come across in Engage. He outclasses most Snipers you could have on your team. Since he's another one of the main Lord characters from a different kingdom, he has two special classes.
He joins as a Lord and can be promoted to the Tireur d'elite, which specialises in Bows only. He can reach S rank proficiency with bows thanks to this class, letting him use some of the most powerful bows in the game. Alcryst learns Luna from this class, too, which is a recurring and powerful Skill in Fire Emblem.
6 Veyle - Fell Child (Spoiler)
This character is a huge spoiler for the late-game story beats. Veyle, who you'll know as one of the main big bad guys you come up against, eventually joins your team towards the end of the game. Veyle is another special unit with an exclusive class.
The Fell Child is a significantly busted class, even coming with a weapon only Veyle can use. Using tomes and knives, Veyle's Magic, Strength, and Resistance stats are beautifully high. Usually, enemy units who join you aren't as broken as when you fight them, but Veyle is consistently strong.
5 Diamant - Successeur
Diamant is extremely strong, and you'll notice that his Defence rates will increase as if he were an armoured unit. Unfortunately, he comes with the low Resistance you might expect with the latter class. With that in mind, he has decent Speed, which means most mages won't be able to double him.
Diamant also gets access to S rank Swords in his promoted class, letting him use Legendary weapons like the Caladbolg. Not to mention, Diamant's class lets him learn Sol, a powerful skill throughout the series that restore HP with attacks.
4 Pandreo - High Priest
Pandreo comes in this class by default, and the High Priest class lets your units become effectively invincible to magic because of the incredibly high Resistance growths.
Any unit can become a High Priest, but Pandreo will almost certainly be the first one you come across unless you've promoted another unit to one before meeting him. The High Priest is an amazing healer, getting access to S-rank Staves like Fortify, and they can dish out significant damage with Tomes.
3 Ivy - Lindwurm
By the time you recruit Ivy, you'll have no doubt poured a lot of time and effort into making Celine your mage character. The game is either punishing you for that or rewarding you because now you'll have two extremely strong magic units, but Ivy outclasses Celine in almost every way.
Ivy is this game's Dark Flier, letting her use Tomes and Staves from the back of a damn fancy black dragon. Ivy has incredible mobility as a flier, and her Defence and Resistance, as well as Magic and Speed, will all be comfortably high. Fliers are typically glass canons in Fire Emblem games, but Ivy can stand her ground.
2 Citrinne - Sage
The Sage class is the promoted form for the Mage. Citrinne begins as a Mage and will slowly become a magic powerhouse if you put time and effort into levelling her. The Sage can use S-rank Tomes, giving them access to the game's most powerful spells.
This class is effectively the generic, non-mounted version of Ivy's Lindwurm, so you can't go wrong with having one or two of your units in this class. Having healing Staves is always a bonus for classes in Fire Emblem, and the Sage is no exception.
1 Chloe - Griffin Knight
Chloe is an excellent character, filling the typical Pegasus Knight trope that Fire Emblem loves to repeat. As you might expect, Chloe is fast and strong, and her Resistance to magic only gets better the more you level her up.
Griffin Knights lack any Defence growth rates, meaning you'll have to rely on individual character growths to fill this in. Chloe doesn't have the best Defence, either, but she will be fiendishly tough to hit if you ramp up her Avoid stats; doing so will allow her to shine as one of the better Avoid Tanks in the game.