The Philosopher's Stone, the Red Stone, the Fifth Element; known as the ultimate amplifier used in Alchemy. It has appeared in many places; invisible to those who do not look for it. It appears in the text of the bible; Revelation 2:17 stated in any version:

«مَنْ لَهُ أُذُنٌ، فَليَسمَعْ ما يَقُولُهُ الرُّوحُ لِلكَنائِسِ.

مَنْ يَنتَصِرُ، أُعطيهِ مِنَ المَنِّ المَخفِيِّ، وَأُعطِيهِ حَصاةً بَيضاءَ مَكتُوبٌ عَلَيها اسْمٌ جَدِيدٌ لا يَعرِفُهُ إلّا مَنْ يَأخذُ الحَصاةَ.»

This "Elixir of Life" is found in writing as far back as Cheirokmeta by Zosimos of Panopolis around 300 AD. Whether one believes in such a mystical object that is said to grant eternal life to its user or not, the Philosopher's Stone is sought by many around the entire world.

I, myself did not believe in such things when I was younger. Though, after meeting the youngest state alchemist and his younger brother who wore a large suit of armor, I learned that many things are not as they appear. That, and meeting them was only the beginning.