The warrior's ashes are a key item in Drakan: The Ancients' Gates. It is one of four items that Rynn must collect in order for Zeggoro to dispel the magic barrier blocking access to the land of Shiverbane.
The urn containing the ashes is located in the Forgotten Tomb, east of Ravenshold. To enter it, Rynn must first assist the Northman blacksmith, Volgen, to uncover the fate of his brother, Sebborna, at the hands of Daemog the yeti. By finding Sebborna's journal, Volgen is satisfied and produces a key that will allow Rynn to enter the crypt.
Drakan: Order of the Flame - Drakan: The Ancients' Gates