While browsing through my Army book, I noticed the virtue of Empathy erm when can i use that for a getting effect. Then all of a sudden a light bulb appear above my head.

Right enough of the blabbering and here is what i thought of.

Paladin - Virtue of Empathy, Knight's vow, Morning star, Enchanted shield.

This makes a really good character for defending so then i thought what to protect. Then i thought what about defending the Trebuchet.

So what do you guys think. Good idea or bad?

Hmmm.... bad, I think. True, your paladin will splat a lot of war machine hunting types, but they'll be getting the charge, so there's an equally good chance that, after they're gone, the crew will also be dead, and you'll be unable to fire the machine. Secondly, the great virtue of the Trebuchet is its cost-effectiveness... having a tooled-up Paladin sitting there as "insurance" against a charge is going to be expensive, and in a lot of games the Pally might do nothing at all, as the Trebuchet is never charged.

Always put a combat character where he can take the fight to the enemy, should he so wish. I think the VoE is probably designed to allow a Paladin to bolster a unit of Men at Arms or Grail Pilgrims, and that's the use I'd recommend.

Besides, the Morning Star of Fracasse is a bit expensive if the only thing you want is the +2 Strength. It would be better to give the knight the Questing Vow and equip him with a heavy weapon (and then, you can drop the Enchanted Shield too and just give him a normal shield).

I'm pretty sure he meant a normal morning star (yes, bretts can take them).

I'm pretty much in agreement with Chilli here, it's too many points on something that isn't goin to be a lot of use.

If you're really worried about the trebuchet: maybe get a couple of small units of bowmen. Deploy one on each side of the trebuchet, as close as possible and an inch in front. Make it hard for your opponents to charge the trebuchet without hitting the bowmen. If it is threatened, countercharge the attackers.

Similar effect, but saves a character slot and at least if the trebuchet isn't threatened, they can shoot stuff.

If you really want to take a Paladin to guard your Trebuchet, make him as cheap as possible and give him the MINIMUM amount of wargear: Virtue of Empathy, shield, and maybe a morning star. After all, he won't be seeing combat much, so there's no point in him being tooled-up with magic items.
Though, as has already been said, a clever enemy will just kill off the weaker crew members. Not only will this render the trebuchet inoperable, but there's theoff chance that it will allow the attackers to win combat and potentially run the Paladin down, thus giving your opponent MORE points in addition to killing the Trebuchet.