Palenke Stone (パレンケストーン, Parenke Sutōn) and the Tangiers Stone (タンジルストーン, Tanjiru Sutōn) are two powerful artifacts kept in Green Hell for safe keeping. The elders believe that these twin gems balance one another out and keep the village safe. They are best known for being stolen by Amakusa and Mizuki in order to raise Ambrosia.
Also known as "Lapis Upirenke". This artifact was created by Ambrosia and separated from him when he was banished to the demon realm. He needs this gem to help siphon the souls in the Tangiers Stone and resurrect his body. It is a powerful gem that is spiritually adept and capable of various abnormal feats. Depending on the heart of the user, it can release holy or evil energies. Amakusa initially steals it to bolster Ambrosia's resurrection though he also uses it to perform various forbidden arcane arts, most of which includes defaming the shogunate by destroying his castles. By contrast, Tam Tam used it once in the past to heal his sick village.
In Green Hell, it is revered as the Holy Gem.
Also known as "Lapis Utuwarentel". It is actually believed to be stronger than its counterpart but its true abilities were sealed long ago. If these two gems are active and in his grasp, Ambrosia could become a supreme being and raise himself from the depths of the demon world. It needs four heroic souls who walk the land as "demons" to break the seal. The required four souls are:
- Haohmaru - Crimson Gem Soul (紅珠魂, Koujyukon); required as the root gem
- Jubei Yagyu - Blue Gem Soul (蒼珠魂, Sojyukon); needed for self-healing
- Kyoshiro Senryo - White Gem Soul (白珠魂, Byakujyukon); grants limitless movement
- Neinhalt Sieger - Black Gem Soul (玄珠魂, Genjyukon); gives unsurpassed vision. Known as Freiden Edelstein in his home country.
The naming motif of their souls' colors are reminiscent of the mythological colors for the Four Gods.
In Green Hell, it is referred to as the Demon Gem. It is alternatively known as the "Seed of Destruction" in China.