Kamen is a dwarf trapped in the Underground Pass. He came to the pass along with Klank and Niloof seeking rare ore, but was trapped there by the evil created by the mage Iban. He helps you during the quest by giving you food.
After the first free gift of food, and during subsequent quests, he will charge 75 coins for a 'dinner' of meat pie, bread, and stew (these 3 items, when consumed, heal 28 hitpoints in total). Alternatively, during the Underground Pass quest, you could accept his offer to drink his homemade brew, but temporarily be drained by 4 Agility levels.