Andraste (5e Equipment)
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Wondrous Item (arcane focus), legendary (requires attunement by a wizard)
Andraste is a teardrop shaped crystal arcane focus, meant to be mounted to the top of a staff. Its point is a dark purple, and it eventually fades to black at its blunt end. Whenever any kind of light is shone directly on the focus, it shines a bright sky blue. The crystal is cold to the touch until it is used to cast a spell, at which point it heats up significantly, to the point of burning the user's hand. Whenever Andraste is found, it's in the cover of an old, weathered book written in deep speech. The words of said book are hard to read, as they seem to shift and warp.
Overclock. Whenever a spell of 1st-level or higher is cast using Andraste, the wielder can choose to take psychic damage equal to 1d4 x the spell's level. If the spell does damage, the spell also deals half that much extra damage to its target. If not, the DC of that spell increases by the number of d4s.
Inner Focus. Three times a day, when you must make a Constitution saving throw to maintain concentration on a spell, you may choose to give yourself advantage on that save. Alternatively, you may have two concentration spells active at once, but you have disadvantage on all Constitution saves to maintain them. You regain all uses of this ability after a long rest.
Preparation. During a long rest, before you regain your spell slots, you may choose to store a spell in Andraste. You act as if you were casting the spell normally, using a spell slot and applying effects, including Overclock. Then, at any time before your next long rest, you may cast the spell without using a spell slot, and as if its casting time was 1 action.
Grasp of Fear. You may use your action to speak a command word that only Andraste knows. When you do, choose up to six creatures within 30 feet of you. Ethereal black tentacles shoot out from Andraste and attempt to attack those creatures. Those creatures must make an Intelligence save against your spell save DC or take 4d6 + your spellcasting ability modifier psychic damage and be stunned for 1 minute. A stunned creature may repeat its saving throw at the beginning of each of its turns, ending the effect on itself on a success. You cannot use this ability again until you finish a long rest.