[Baalz]

Hmmm, don't know about the Iron Angel obviously but I've had some luck using Black Lords as thugs. Before I get into them specifically let me address your broader question about how to build thugs.

To build a thug you need as many of the following as possible (after any magic buffing you can do):
Good hitpoints or mistform
Very good protection (25+)
Very good defense (25+)
As many ways as possible to negate some percentage of attacks (ethereal, lucky, awe, vine shield, fire immunity, etc.)
An area of effect weapon (fire/frost brands are obvious choices)
Regeneration and/or a lifedraining attack
Good reinvigoration and/or a lifedraining attack
Low encumberance
A cheap price tag - thugs should be relatively disposable

Now, usually you can't get all that in one package and some nations have better choices available than others. Ulm's Black Knight has more than one achillies heel, but he does have a couple things going for him. First and foremost, he's one of the cheapest thug chasises you'll find and with Ulm's forge bonus he's also gonna be one of the cheapest to equip as well. With a dwarven hammer Ulm's smiths only pay 2 gems for a 5 gem item, and that's were you want to aim for your disposable thugs. Since they're so cheap, you also want to use more than one at a time together(a bit different than most thugs), 2 or 3 riding together is more along the lines cost wise of other thugs - what else can you field for just over 100 gold and around 10 gems? You've also got to keep in mind their weaknesses and only deploy them where they're effective - generally raiding PD and avoiding any mages. Most any player with any experience will drop them like flies when they run into any real magic opposition so stay away if possible. Obviously you'll want to configure them differently depending on what they're actually fighting, but here are some things I found to be very effective:

Barkskin amulet - get an indie mage to forge. You don't get a forge bonus but this still only costs 3 gems and ups their protection over 30.

Fire brand - 2f 2e, AOE and armor piercing

Shield of gleaming gold - awe +0 can go a long way against chaff

Pendant of Luck - 2 pearls? Hell yeah

Girdle of strength - 2 earth reinvig goodness and the extra strength makes that AP firebrand that much better against larger foes.

Amulet of MR /Lead Shield - still not great MR, but better than nothing.

Charcoal shield - killer against some PDs

Resistance items - fire/lightning rings with smiths, frost/poison however you can will counteract the focus of many nations.

They're not unstoppable killing machines, but properly deployed they can be well worth their cost.