The chief cleric of Lunas, the elf Isato is the right-hand man of Oracle Haswar. Isato originally hails from the hidden elven village of Alseid, but became a priest in Lunas. He first meets the Prince when he is taking Lymsleia to be purified. He serves as a guide for the Prince and shows him around Lunas. He is quick to chastise a priest for speaking foully to the Prince, and believes that Haswar's wish that she not become Queen take precedence over the wishes of the other priests.
Isato serves Haswar because she protects the river of Lunas, which has heavy deposits of gold in it, from being mined by the greedy nobles. Because mining of the river will ruin Alseid, he needs to protect it and, no matter the protests of his elven comrades, not return home. Because Isato believes so strongly in protecting the rivers, he is quick to punish Lun and Logg for mining the gold dust, despite the fact that they did not ruin the river by themselves. He agreed to Sialeeds's plan because the Oracle thought it was a good idea and because Raftfleet would punish the two anyway.
Isato plays host to the Prince after the Godwin attack on Sol-Falena, and, at the Oracle's request, leads them through the elven path to Barows territory. He stays as Haswar's assistant, even though an elf from his homeland, Urda, insists he come back home to stay out of the human conflict. But since he believes his duty is to Haswar, he always refuses her insistence. Haswar eventually decides to leave Lunas, though, wanting to join with the Prince and be a mother figure, even if she can't replace Arshtat or Sialeeds. Isato agrees to come with her.