1. Speak with Dhong the Guard at Baryo Mahiwaga (ma_fild01 239, 253) and ask him about his Guard Dog Vantai. He tells you that Vantai needs to eat Purified Spirit Bones.
2. He tells you that he can't move away from his spot. So he asks if you can get the bones for him. You'll need a Holy Water to purify them by speaking with Kiko in Mumbaki (ma_fild01 261, 206). Accept his request and gather 10 Evil Spirit Bones.
3. After acquiring 10 pcs. of it and having 10 Holy Waters in your inventory at the same time. Speak with Kiko in Mumbaki (ma_fild01 261, 206) and request for a Purification Ritual. He then gives you 10 Purified Spirit Bones.
4. Take the Purified Spirit Bones to Dhong. He thanks you for the job and rewards you with EXP, Job EXP and 1 Lesser Agimat.
Spirit Bones are automatically added to your inventory when you kill a monster. Most usually Tikbalangs are the most effective.
If you speak with Kiko with more than 10 Spirit Bones in your inventory, he'll consume all of them.