The First Berserker: Khazan: Merchant Locations & Interactive Tracking Guide

Found by the wall, on the patch of land in the poisoned water. You can purchase consumables from him and sell your unwanted items.

Found in the study room. Oksana is an alchemist who can extract Lacrima from items. Use her services to extract Lacrima from the items you don't need, then use that Lacrima to upgrade Khazan's stats.

Found next to the ladder. You can purchase consumables from him and sell your unwanted items.

Found behind the Battered Blade Nexus. You can speak to her on various topics, and you can also exchange the Soulstones you have gathered to increase your stats.

Found next to the chest on top of the stairs. Oksana is an alchemist who can extract Lacrima from items. Use her services to extract Lacrima from the items you don't need, then use that Lacrima to upgrade Khazan's stats.

After returning from the Embars Ruins, Oksana moves to the room on the lower floor.

Found in the study room. Oksana is an alchemist who can extract Lacrima from items. Use her services to extract Lacrima from the items you don't need, then use that Lacrima to upgrade Khazan's stats.

Found on the central plateau. Speak to him to progress the story (unlock Phraugh Village) and access his services. Duimuk sells consumables and gear, and he buys every type of item you want to sell.

Found next to the piano. You can purchase consumables from him and sell your unwanted items.

Found next to the table and the bed. You can purchase consumables from him and sell your unwanted items.

Found on the balcony that you can reach via the drop point.  You can purchase consumables from him and sell your unwanted items.

Found next to the stairs in the starting area. Talk to him for the Jar Enthusiasts side mission. Also, you can purchase consumables from him and sell your unwanted items.

Found on the upper plateau after completing Jar Enthusiasts. You can purchase Helms, Consumables, and Materials from him. Also, you can sell your unwanted items to him.

Found in the study room after saving him from Aratra's lair. After completing the Blacksmith's Heirloom side mission and returning to the Crevice, the blacksmith can craft and dismantle gear for you.