Ankoku Temple is a Buddhist temple which lies on top of a small hill at Ryoshima Coast, near the series of hills and small mountains where the Guardian Sapling of the location is. Surrounding the temple is a wall, lining the hill's top. In front of the temple, down at the base of the hill is a cemetery with graves of travelers who hadn't got to Sei'an City. To the left of the cemetery is the temple bell with a sign that says not to ring it. From the base of the hill, a steep staircase leads up to the temple, with roofs above parts of the staircase. The interior of the temple holds a treasure chest with an Incense Burner and outside there is a cat to feed. Behind the temple, on the cliff is a secret cave, hidden by a vanishing rock wall. Inside the cave is a well, which holds an a tunnel that leads to a side room of Queen Himiko's palace. The tunnel is also where the body of the real Rao is dumped by Ninetails after it had murdered the priestess.
Amaterasu and Issun can access the temple as soon as Ryoshima Coast is cleared of its curse and the Guardian Sapling is restored, although there is little of interest compared to neighboring Sei'an City. However, they are forced into visiting later after King Wada's last vision reveals an image of Rao being attacked by a large, shadowy demon. Fearing for Rao's safety, Amaterasu and Issun rush to the temple, only to find "Rao" lead them, from a distance, to the secret cave. Following the tunnel, Amaterasu and Issun got to Himiko's Palace, and after getting to the queen's throne room, they found "Rao" standing there, trembling in fear of a "demon that murdered Queen Himiko". However, Amaterasu is not fooled, and attacked the "priestess". After "Rao" drops the facade and reveals itself to be Ninetails, and Himiko's murder is discovered, it becomes apparent that the skeleton in the secret passage is none other than the real Rao, and the Rao that led Amaterasu and Issun to the passage was her ghost. Subsequent trips through the passage to examine the skeleton will cause Issun to say "Poor busty babe..."
The temple has been occupied by a new priest since Rao is no longer there. The priest has lost some of Rao's treasures and requests that Chibiterasu bring them back.
- "Ankoku" (餡刻) can be written by two other kanji with the same pronunciation (being homophones),「暗黒」, which means "darkness".
- More importantly, the kanji「暗」(「あん」?; an; darkness</i>) has the same on'yomi pronunciation as that of 「安」 (「あん」?; an; peaceful, tranquil<i>), which is a common way to name Buddhist temples. Therefore, Ankoku Temple's original name, specifically the kanji 「餡」, would refer to both "tranquil" and "darkness".
- The statues inside Ankoku Temple appears to be Bodhisattvas, a kind of archetypal beings seen in the Japanese Buddhist pantheon.