Scions

they can start above lvl 2 once you have some building that do that and/or if you give them the right perks.

i use them as defenders, what they do quite well

and as commanders (to give bonusses to the whole army).

i have not tried to use them as the other classes yet.

i never use more than 2 of them in a full army stack, cause as you said in the beginning (before they level up a few times) they are quite fragile. but the more levels they get, the more powerful they become.

Instant governors - decent fortress to provide a few free level-ups, plus the trait that grants a free level, and you can pop out a few of these with Commander and a couple levels of the administrative traits fairly quickly. Also works for the Field Commander side of things, though it takes a little while to get to the really good bonuses.

If you have access to the Decalon spellbooks (Pariden or a custom faction with the Decalon is nearby and not at war with you, or you have a custom Empire with that trait), they can also make for decent damage mages. Air I or Water I are all you need for a decent support caster, and these you can get just from reading the spellbooks; Fire II/III is the shortest path to good damage spells but means you'll need to gain an extra level or two after reading the spellbook, and the same goes for Water IV. If you don't have access to the spellbooks, though, I wouldn't bother making these into mages unless you like summoners or want Horrific Wail casters.

I personally would not go for any of the direct combat classes on a single-figure unit.

Yeah, that is what I thought. The flavor text said "best fallen warriors" or something, and that just does not seem to be the case.

Technically, per-figure a Sion can be the best Fallen warrior - they can get all the bonuses a fortress or enchanted city can give and they can get the same traits as direct combat champions (which ultimately means that Sions and Henchmen make superior direct combat champions than champions do), and they can start with the best equipment you can produce, which you can subsequently replace with the best equipment you can find. The problem with using them as a direct combat unit is that by the time you can get them, you could have (and be facing) four or five figure units with mid-game weapons and armor. A single-figure unit does not compare well to that at all, since the same equipment means that the units will be dealing on average the same per-figure damage to one another, and if they're both coming out of a decent fortress (or both are not coming out of a decent fortress) they have enough accuracy that neither really has any hitting advantage (although the Sion wouldn't really have much of one anyways, since hits are computed per figure, so a three man unit with a 70% hit chance has three 70% chances to hit rather than one 70% chance to hit for lots of damage - I'm not great at computing probabilities, but I do know that three 70% chances to hit for damage means a much better than 70% chance to hit for any damage, and when you've got the same equipment on a low-level Sion or Champion, that means that the regular unit is probably at least as good as the Sion or Champion).

Scions are really only useful if you have the ability to train them and be higher level.  They can be very useful, but usually only in the later part of the game, you know, when you've already won. 

There is/was also a Scions mod for download....saw it another thread. I'm just about to explore the possibilities in a game I'm playing.

does anyone know if the mage path works for scions ? I keep wanting to write sion.

Edit: that would be without purchasing any of the books from decalon. henchman can use th path spells without them but scions don't seem to be able to...

I never tried sion, but it seems it's just a slightly weaker version of altar's henchmen. CMIIW

Henchmen spells are incomplete version of the real spellbook path. That being said, hencmen can be build as an excellent mage without decalon books because there are some very useful spells on the henchmen minor spellbook path, like growth/shrink, storm, haste, slow, etc plus the path of the mage.

Because of path of the mage, henchmen is much much better mage compared to original FE's henchmen mage, because there are many good traits in path of the mage, the summoning line make the game very easy at harder difficulty. I assume scion can access this, if yes then mage scion is as good as henchmen, well..., maybe a slightly lesser version of it. The only different is the incomplete spells which henchmen has (though some are excellent spells)

One distinct advantage of Henchmen is that they can start off with Life Adept and quickly get the Heal spell.

They also make great governors if you have a good fortress to produce them (with custom design).  Mine start off with Administrator II and Road Building.  They reduce unrest by 40 points.

Create a scout with a horse.  Use it to gather free goodies.  Could also use it as a delivery service to transfer goodies between armies.  Can also be used to capture outposts.

Yes, not only heal but it can also have growth/shrink, which is the best spell from adept books (henchmen spellbook).

I guess why Sion is slightly weaker than henchmen is because it is available to all fallen factions, while henchmen is only for altar, other kingdom faction doesn't have it.

Wait, Sion can't be a governor?

apparently they can be assassin, defender, warrior. It does clearly say in the description that they can not use magic - I wish they had a different menu at level up perk select when choosing a path/ class to show this.

Yeah that's a good idea, and show the traits info on all class too.