Staff of the Arcanum (Patreon)

Staff, legendary (requires attunement by a wizard)

This staff is made of both raw and polished obsidian. Your Intelligence and Wisdom scores each increase by 2, up to a maximum of 22, while you're attuned to it. In addition, you can use your Arcane Recovery twice between long rests, instead of once.

This staff can be wielded as a magic quarterstaff that grants a +2 bonus to attack and damage rolls made with it. While you hold it, you gain a +2 bonus to spell attack rolls. A target hit with the staff takes an extra 1d10 force damage and is pushed up to 10 feet away from you.

Spell Storing. This staff stores spells cast into it, holding them until you use them. The staff can store up to 5 levels worth of spells at a time. When found, it contains 1d6 − 1 levels of stored spells chosen by the GM.

Any creature can cast a spell of 1st through 5th level into the staff by touching the staff as the spell is cast. The spell has no effect, other than to be stored in the staff. If the staff can't hold the spell, the spell is expended without effect. The level of the slot used to cast the spell determines how much space it uses.

While holding this staff, you can cast any spell stored in it. The spell uses the slot level, spell save DC, spell attack bonus, and spellcasting ability of the original caster, but is otherwise treated as if you cast the spell. The spell cast from the staff is no longer stored in it, freeing up space.

Sentience. The staff of the arcanum is a sentient chaotic good staff with an Intelligence of 18, a Wisdom of 15, and a Charisma of 13. It has hearing and darkvision out to a range of 120 feet. The staff communicates telepathically with its wielder and can speak, read, and understand Common. While you're attuned to it, it also understands every language you know.

Personality. The staff of the arcanum is bookish and, at times, stuck up. It enjoys unraveling puzzles. It refuses to lend its strength to liches, however, preventing them and similar necromancers from using the staff's properties. At the GM's discretion, the staff may choose to cast a stored spell on its own (no action required by you).

'Tis said the horse will choose his rider, the ship her captain, the song its singer.

And so, too, have I chosen you, arcanist. With your heart and mind lent to mine, who knows what mysteries we'll unravel?

…I'm giving you quite a roguish grin now. It may be hard to tell, but you should be informed.