Arcanist’s Blade
Weapon (any sword), rare (+1, 1st level), very rare (+2, 2nd level), legendary (+3, 3rd level) (requires attunement by a spellcaster)
This surprisingly lightweight sword feels like a wand in your hand. While holding this magic weapon, you gain a bonus to attack and damage rolls made with it, and you gain a bonus to spell attack rolls and the saving throw DCs of your spells. The bonus is determined by the weapon’s rarity. In addition, you can use the sword as a spellcasting focus.
When you roll a 20 to hit a creature with this sword, you regain one spell slot. The slot must be the lowest level spell slot you have missing and the maximum spell level you can regain is determined by the weapon’s rarity.
As you grasp the hilt of the longsword, you can feel your mind extend into it. Runes alight, one-by-one down the blade. This is a weapon of arcane power.