Iudex Gundyr is the first Boss in the game. He is part of the tutorial section and quite easy to defeat. To start the fight, you must pull a spike out of his chest. Attack him immediately to take away a good chunk of health before he gets up. Approximately halfway through the fight, he will transform and get more aggressive. He is defenseless while transforming. His attacks can be parried with a shield, or simply dodge and try to get behind him. If you play as a sorcerer or pyromancer, keep your distance. You can also use your three estus flasks to refill health. You will get an achievement for defeating each of the eighteen Bosses.