It took on half an Eldar army. Their black, blues and whites did little to dent its fervour.
Then a full Tyranid force descended upon it. From humongous monsters to lowly hordes, it took them all on, and finished them in good time. Yet their numbers certainly took a toll, and while it showed no ill constitution, its will was corroding within.
Then came the Sanguinary Guards. Their armour and spears had at it, and its blunt fortitude could take no more. Ultimately their wings became its undoing, shattering its will, and breaking its impossible spirit.
To which I say... "DAMNIT!"