LogFAQs > #979670613

For 3, the game curves EXP sharply, so it is pretty easy to have units who are behind on exp catch up, as long as they fight next to units strong enough to carry the squad as a whole. Because of this, there really isn't anything to lose by using Josef as much or as little as you want. He can trivialize a lot of the early game for you and let you do missions "out of order" a bit (e.g. you're supposed to get some anti-magic units before you do Auch's mission, and the game will try to warn you, but Joseph can just hard carry the mission with his crazy stats and ability to protect his squad from magic assists).

However, Josef is designed like a Jagen in the sense that he has horrible stats for his level. He is also specifically given an incredibly lopsided growth curve where he gets very, very poor stat gains for his first 20 or so level-ups, but absolutely stupid stat gains for his last few levels (think 3 or even 5 points per stat per level) so he suddenly ends up being appropriately statted for postgame (not better than everyone else, but on par), should you want to use the Paladin class at that point (which you may no longer have any interest in). He can also be used in the midgame for things that don't rely on stats as much, like throwing out Holy Shield and heals, but there are a lot of much more impressive supports you'll get that make this pretty lackluster.