Bastard's Sanction

An ancient staff used by one of the architects of the Cathedral before it's fall. It's said to be possess the memories of the wielder before it. 

Only usable by Clerics, Sorcerers and Wizards

Wielders can make a INT save whenever they cast a Spell during combat and if the save is 15 or higher, they get 1 extra Spell Slot. If this action is repeated 3 times in succession, this item will explode. All combatants must make a DEX save and CON save that both exceed 15, otherwise they take 2d12 Radiant damage. 

Notes: Proficiency: Ability Checks, Bonus: Arcana, Advantage: Intelligence Ability Checks