Gas Powered Games' official Dungeon Siege II website has been updated with information about powerful sentinels called Rust Guards. Their description to follow:
Ancient statues from a lost age, these cold-eyed sentinels guard powerful artifacts from those who would abuse them. Though they may stand silent and unmoving, they burst into action at the slightest trespass.
They wield four massive blades with clockwork precision, and are capable of using all four simultaneously with devastating strength. They feel no pain, never tire, and are very difficult to destroy. Only a fool would dare to stand toe-to-toe against one.