Resting in a small chest set on a pedestal kept in a room populated with various artifacts lay two spheres that are roughly 5" across. One, glowing a brilliant blue-white, as a flame. The other darker than the blackest night. Together, the orbs have little effect. But if one or the other is uncovered or the orbs are separated, they produce a radiant blinding light, or an all-consuming darkness for ten feet around them.
The characters may find such orbs in an artificer's private collection, or in use as part of a trap or weaponized by those with truesight.