Ruby of the War Mage
Wonderous Item, Rarity Varies, (Requires attunement by a spellcaster)
Common: Etched with eldritch runes, this 1-inch-diameter ruby allows you to use a simple or martial weapon as a spellcasting focus for your spells. For this property to work, you must attach the ruby to the weapon by pressing the ruby against it for at least 10 minutes. Thereafter, the ruby can't be removed unless you detach it as an action or the weapon is destroyed. Not even an antimagic field causes it to fall off. The ruby does fall off the weapon if your attunement to the ruby ends.
Rare: You gain the benefits of the common version. You also gain a magical +1 to attack and damage on melee attack rolls, and +1 to spell attack rolls.
Very Rare: You gain the benefits of the common version. You also gain a magical +2 to attack and damage on melee attack rolls, and +2 to spell attack rolls. Additionally, you gain benefits when casting spells from certain schools of magic. When making this item, roll twice on the following table (or DM's choice) and gain effects from the following table when you cast a spell corresponding to the school of magic.
Legendary: You gain the benefits of the common version. You also gain a magical +3 to attack and damage on melee attack rolls, and +3 to spell attack rolls. Additionally, you gain additional benefits when casting spells from certain schools of magic. You gain all effects from the following table when you cast a spell corresponding to the school of magic.
| d8 | School | Effect |
|---|---|---|
| 1 | Abjuration | Gain a bonus to your AC equal to half the spell level (rounded up) until the end of your next turn. |
| 2 | Conjuration | You can teleport to an unoccupied space you can see within 60ft. |
| 3 | Divination | You gain advantage on the next attack roll you make. |
| 4 | Enchantment | You gain advantage on the next Intelligence, Wisdom, or Charisma saving throw you make. |
| 5 | Evocation | You can make one melee weapon attack as a bonus action. |
| 6 | Illusion | You become invisible until the end of your next turn unless you make an attack, make a damage roll, or force a saving throw. |
| 7 | Necromancy | Gain temporary hit points equal to the double spell level (rounded up). |
| 8 | Transmutation | Gain resistance to acid, cold, fire, lighting, or thunder damage for rounds equal to the spell level. |
You can also roll a d10 (or just use these) if you use the Chronurgy and Graviturgy schools found in the Explorer's Guide to Wildmount
| d10 | School | Effect |
|---|---|---|
| 9 | Chronurgy | Gain the effects of the Haste spell (with no after effects) until the end of your next turn. |
| 10 | Graviturgy | Gain a fly speed equal to your walking speed for rounds equal to the spell level. |