Harbinger Blood Infusion

From the Aerbax's Prodigal Harbinger quest introduced in Dark Materials.

Harbinger Blood Infusion
Value: 20 10 Burden Units
A potion of multihued liquid. It glows with a soft white light. Drink me. Casts the following spells: Harbinger Blood Infusion Spellcraft: 300 Mana: 50 Spell Descriptions: Harbinger Blood Infusion (The Harbinger's blood suffuses your being increasing your natural armor by 300 points.)

Notes

• Give the Blood of the Harbinger to Issk (instead of the Emissary) and you will receive this potion.
• This potion can be turned back into Issk for 10% xp.
• Stack Size: 100
• Lasts 15 minutes.

You cast Harbinger Blood Infusion on yourself, surpassing Executor's Blessing