It's a great little system and we absolutely smashed it. However, it's a legacy game and so you draw a card to see what gets added to the game after each expedition...... and we drew the mighty Chaos Lord so we may see him sooner than we'd like - yikes!
Barek is a dreadnought from the Salamanders Legion, one of those massacred in the drop. The Salamanders revere and hunt giant lizards on their home world, hence the trophies on the carapace. He fought bravely in the cauldron of battle, but suffered critical damage to his left arm, right foot and cogitator system.
Repairing his cogitator system, but unable to save his original left arm and right foot, they salvaged alternatives from a Dreadnought from the Word Bearers legion - one of the traitor legions.