Advanced magic and dark tales.
Dark Souls 3: Karla
Karla is something of a back up NPC; she can be used to keep Irina of Carim alive, while still being able to purchase the spells Irina only sells if you risk her death. She sells both sorceries and pyromancies.
Recuit Karla by unlocking her cell in Irithyll Dungeon; the key can be found at Profaned Capital.
Give the Izalith Pyromancy Tome and the Grave Warden Pyromancy Tome to Karla to expand her inventory. Cornyx will not accept these tomes.
Although she’ll refuse at first, you can press Karla to accept the Londor Braille Divine Tome and the Deep Braille Divine Tome. This will ensure Irina’s survival while still allowing you to purchase the spells contained therein. There seem to be no negative consequences.