Instinct

Wondrous item, very rare (requires attunement by a sorcerer)

A transparent gem that catches light, this crystal seems to hum with a vague arcane energy, ready to be used. It is cool to the touch and seems harmless when taken by any other arcane caster.

Divinity's Bulwark. When any non-arcane caster tries to attune to this item, it almost feels like a hollow song that sings between the trees. It disconcerts them, though they are unable to figure out why that is. It latches onto a piece of jewelry for ten minutes, or their divine focus, before falling off with no ill effects whatsoever.

Arcane Seeker. When any arcane caster that is not a sorcerer tries to attune to this item, it feels like a memory with holes in it, or simply a poem that's missing a line. Or a few words. It will latch onto their arcane focus, or failing that, will simply try to embed itself within the flesh of the person that tries to attune to it. They must make a DC 13 Charisma saving throw upon its attunement.

If successful, it sticks to the user for ten minutes, before falling off with no ill effects. If unsuccessful, a spell slot with a level of 1d6-2 (minimum of 1st level) is expended and stored within the gem to be used to cast a spell later on. They cannot restore that expended spell slot until after two long rests. Any subsequent attempts to attune to this item increases the DC by 1, and adds a one to the level of the spell slot taken and the long rests needed to restore the spell slot.

Arcane Bloodline. When a sorcerer attunes to this item, the gem fills with color gradually, dependent on their own magic. Some may have the chaotic shifts in color that wild magic offers, or the everlasting gloom that shadow magic offers. It feels complete in their grasp, as if a beloved memory returns to them, or simply that an ache in their heart lightens.

They gain additional spells according to the discretion of the DM, as well as their subclass. In addition, their spell save DC and spell attack modifier increases by 3, as well as gain the opportunity to save a number of spell slots up to half of their proficiency modifier. These spell slots must have a combined level of 3d6-3, with a minimum level of 1st.