You have already completed the initiation rite.

This is my father's Bonebiter Bow. You have completed the initiation rite. I name you %PCName, Clanfriend of the Ashlanders. Keep my father's bow, and bear it with honor. You are a friend of our tribe, and may rest in any Urshilaku bed, but do not harm other tribe members, or take their things. And now I will fulfill my other promise. Go to the wise woman's yurt, and Nibani Maesa shall examine you, and test you against the Nerevarine prophecies.

Until you bring me the Bonebiter Bow, you may not go before Nibani Maesa to be tested for the Nerevarine prophecies.

To be adopted into the tribe, you must undergo a harrowing. In a harrowing, you will be judged by the spirits and ancestors to see if you are worthy. Go to the Urshilaku Burial Caverns and fetch me Sul-Senipul's Bonebiter Bow. Sul-Senipul was my father, and his spirit guards his bonemold long bow deep in the burial caverns. Return to me with this bow, and I will adopt you into the Ashlander tribes as a Clanfriend.