Mahakaman Spirit is an ingredient required for crafting Dwarven Spirit (which is used in crafting potions). When you explore and loot a lot, you’ll find that you’ll have an abundance of Dwarven Spirit. But if your character is still new you might not have any stock of it and might want to craft some potions already. Therefore you’ll need some Mahakaman Spirit.
You need 2 Mahakaman Spirit bottles, 1 myrtle petals and an empty bottle to craft Dwarven Spirit.
Mahakaman Spirit can be bought from most Innkeep merchants. The Innkeep here at the Crossroads sells Mahakaman Spirit. When bought, you can reset his stock again by just closing the merchant inventory and selecting the buy dialogue again.