Soilder Est promotion thing. How should I do it?

Okay. I currently work on a fire emblem rom hack and I plan to add an Est character.
My idea is that the Est will be a soilder as a play on Soilder’s being bad.
My game will have 10 chapters and I plan to add the Est in chapter 8.

I was currently thinking about that unit having both double exp and double weapon rank growth to allow for it to easily grow. But I also want to add a big reward, maybe by giving the unit a prf weapon and giving it really good promotions. So I am thinking what would be a good Est promotion reward?

Maybe I can make it a prf sword that can only be used after becoming either a paladin or a general? But paladin or general would be pretty one sided. Maybe I can make promotions into non lance classes but the Est keeps their lance abilities (would just need to add lance animations to the choosen classes) .

Anyhow I would appreciate some help as I want to make a small but good game.

Btw here is my hack as seeing the hack may help judging what would fit it: Dance of Glory [Demo] [Looking for help] - #26 by TritraSerpifeu

Although I am not entirely sure about Discipline, I do agree with Paragon being an option to increase how fast this unit can develop, but whether or not the unit can grow is entirely dependent on the enemies it fights across the very limited span of time they’re playable for.

While other “snowball” skills such as Blossom/Aptitude can be considered as well, the concept of a reward for leveling the unit up - investing on it can arguable make using the unit worth-ish.

Though (don’t quote me on this), you could give them this prf (as a sword or any other weapon type) and still let them access it if they promote to Halberdier for example.

Yeah. I need to allow there to be low defense enemies that a soilder can level. Even if it a fragile or magic unit, I need units that are defeatable.

So I will probably add in res focused units so that a physical attacker, even a weak one, can gain experience on the join chapter. Due to the short lenght of the game I plan that the unit starts on level 1.