Hades' Tower

Here's the real home of Hades, and you can only visit this place after returning Jason's sword to his grave. Rather than fight Hades, our goal here is to dispatch his imposter and rescue him. After rescuing him, he'll wait patiently at the entrance of his tower, and he'll join your party just like Poseidon. As far as treasure goes, the Giant Shield is quite nice, if you haven't already purchased one, and you can grab the MgScale by climbing to the top of the tower, and dropping down the top portion of the central pit there. Also, the small corridor just before reaching the Doplgangr contains nothing but Drain Eyes and DrainMeels, making it one of the best places in the game to level up.