Arcane Annealing

Your body toughens and melds itself and your equipment into a sturdy, wrought iron form. Your AC becomes 10 + your spellcasting ability modifier + your proficiency bonus for the spell's duration, but have disadvantage on dexterity saving throws and ability checks.

As an action, you may choose to focus the power of your annealed form to your arms to resist the blazing heat of the forge. Reduce the AC granted by the spell to 10 + half your spellcasting ability modifier (rounded up) + your proficiency bonus. If you do so, you gain resistance to fire damage and take no penalty to dexterity saves or ability checks for the remainder of the duration.