A sigilist is an NPC class based on the Infuse Scroll feat. The sigilist uses the wizard class as a base, and gains the abilities listed under Spellbook, and Ritual Casting, but does not gain any other special abilities, such as Cantrips, Arcane Recovery, or Arcane tradition. A sigilist can be either arcane based or divine based, but must research or find their “spells” as a wizard would. (Most learn from the base “adept” list).
You can also tap into your reserves of magical energy to create spell scrolls. You can use your available spell slots to create spell scrolls instead of casting them normally. You must finish a short rest, then spend 10 minutes with parchment, quill, and ink to create a spell scroll containing one spell chosen from those you know. Once you have expended a spell slot to create a scroll, you cannot regain that slot until the scroll is used or after 1 week, at which time the scroll loses its effectiveness.