The Achturardackians were pioneers of sigil based magic, and their techniques for building glyphs, sigils and seals remain the foundation of magic inscription.
The relic of an old Sorcerer, the Glyph of Tarnos Krae is a window into the past.
MoonInk: This alchemical product has 101 uses. The Ink/Paint dries to be totally clear and almost unnoticable. Under moonlight, it comes forth as a silver ink. It was originally used by the Elventi to enhance certain pieces of art. It is used by espionage types to produce secret messages, nobles for hiddle plots, and diabolical cultists to write their spell books (usually in books of holy texts, to throw off people reading it).