Once Upon A Time [XXIX]

"Philosopher's Stone: Means 'Sage's Stone'. Also known as: Philosopher's Stone, Heavenly Stone, Great Alchemy Elixir, Red Ultimate Substance, Fifth Entity, etc. Give joy to suffering, and victory to battle , to regenerate the dead, is the promise made by the blood-red stone, which is respectfully called the 'Stone of the Sages'."

This is the entire content of the Sage's Stone in the book "Alchemy Artifacts and Treasures". The English name of the Philosopher's Stone is Philosopher's Stone. Take the first letter of the two words, which happens to be ps. Maybe the ps substance in the diary of the slang refers to the stone of the sage.