Neat item! I guess I need to go play through the Assassin's Creed series—I had no idea the lore got this crazy...
Wondrous item, legendary (requires attunement by a spellcaster)
This perfect bronze sphere is slightly larger than a typical apple, and has inscrutable but very orderly and deliberate lines and patterns etched asymmetrically into its surface. Its scant weight suggests that it is either hollow, or is magically lightened. Once attuned to the orb, you can use it as a spellcasting focus. Your spell save DC is increased by 1 for spells cast using this orb as your focus.
Additionally, the orb has 16 charges, and regains 1d8 charges each day at dawn. As an action, you can spend charges from the orb to cast any of the spells listed below, using your own spellcasting ability modifier. The number of charges required to cast one of these spells is equal to 1 + the spell's level.