You can grind up weak companions by fighting groups of sea raiders, giving that companion the best armor and weapons you've got, then having them challenge the enemy to a duel.

If they win, they get a lot of EXP and you can then invest heavily into strength and iron flesh.

I did this with one of my companions so that she'd eventually reach level 4 in beauty so she could teach the class to my character. This teammate also reached level 24 in the process.

The mountain bandits are also total pushovers once you've got your guys equipped with a lance, a two hander, a shield and usually a throwing weapon.

In the case of heroes like Ten Feet of Blue, I let her keep her weapons since she's fantastic with them and then give her any legendary bows I find.

If someone already has skill in shields, or throwing weapons, it's best to give those items to them.

But the others are all high strength bruisers who wield Sha Horsekiller Blades. These have good reach and decent speed for their price. The village padaos are okay, but the best are there much more rare silver padaos.

Those make the horse killer blade completely obsolete and are plain murder machines.

I have them all invest in enough agility to get to a decent level of riding so they can equip armored horses. That's very important when facing lancers as if their horse dies, the companion is probably going to go down soon after.

First I decide if my companions would make Warriors or Officials (party skill builds, scout, doctor ect) . The Warriors are given horses and stat builds for fighting usually given a great weapon to fight from horses with. Officials are given no horse usually and focus on range weapons, skills which help their build therefore the whole army. I want to get my Warrior powerful enough they can duel and win against sea raider chiefs 100% of the time. A great doctor, scout, tactician are more important overall then a great warrior.

It's a personal choice, but there's seriously some overpowered AI lords out there. [Divine Physician] has a Star Skill that causes you to regen health in battle AND his medical skills are all maxed out.

He's the best medic in the game, in every way. There's another lord who gains skills permanently for every 100 kills he gets. If you're willing to recruit this guy and take him out to grind, he could have literally perfect skills.

And when you raid a village with a small group of guys, it causes the peasants to attack you. Meaning you can score 45 kills per village if want to max this guy out faster.

So I never invest in anything other than combat skills with my tavern recruited companions. The AI lords add a lot of extra planning and strategy to things with how OP some of them are.