Can open the trapped chests in the Undead Pit via the Mage Guild? That's right! Seiman! The chest in the left area has 1x Revive Potion and the one in the right area I need to level him up a bit more before he can open it. Will update this post after I get that chest.
Edit: The right chest contains 2x Necroleach and 1X Zombie Heart. GO SEIMAN!