Staff of the Sangromancer (Patreon)

Staff, very rare (requires attunement by a spellcaster)

A staff created from the solidified blood of a vampiric mage. While attuned to this staff, it merges with your own blood. You can use a bonus action to cause the staff to liquify and retract into your veins or reform in an open hand. While you hold it, you gain a +1 bonus to spell attack rolls.

Vitae Arcanum. While holding this staff you can use your own lifeforce to cast spells. In place of a spell slot, you can choose to expend a number of unspent hit dice equal to the spells level. If you do, roll each hit die, taking necrotic damage equal to the number rolled. This damage cannot be reduced in any way. A spell cast this way cannot be higher than 5th level or higher than your highest level spell slot. Your spell save DC for a spell cast this way is increased by 2 and if the spell would deal damage, it deals necrotic damage instead.

Dark Puppeteer. You can cast Hold Monster from this staff without expending a spell slot. A creature that does not have any blood in its body, such as constructs, succeeds automatically. On your turn you can move the held creature up to 15 feet in any direction using a bonus action. You can use your action to cause the held creature to immediately make a single melee attack against a target of your choice. Whenever a creature fails its Wisdom save to escape it takes necrotic damage equal to 1d8 + your spellcasting modifier.

Once you use this feature it can't be used again until you finish a long rest. You can cast Hold Monster with this property again by using any spell slots you have of the appropriate level or by using Vitae Arcanum.

Curse. When you attune to this staff, its vampiric blood infects your own. You cannot end your attunement to the staff while cursed this way. Your creature type becomes undead, you gain the Sunlight Sensitivity feature. Additionally, you must consume 1 vial of humanoid blood every 24 hours. If you do not, you cannot gain the benefits of a long rest until you do so. This curse can only be removed after finding and slaying the vampire whose blood was used to make the staff.

Blood is life. Eons of history course through the veins of the living. Endless power waiting to be unlocked by one proficient in its extraction. Blood mages can access this font of arcane vitality, restricting its flow in others or causing their spells to surge with life. The cost of this power can be draining, but a true sangromancer can always find a way to renew their strength. After all, blood is life…