Voidblood Heart

The  is a toggeable item that is in the player's inventory upon the player's creation, alongside the Elemental Capsule and Mystic Gemstone, but it can also be crafted at Evil Altars with no materials.

When activated, the status message "Your veins turn black" will appear in chat, indicating the item is currently on and the effects are applied, the player's health will produce a red glow around them. When toggled off, the status message "Your veins turn back to normal" appears in chat, indicating the item is currently off, and all the effects are removed.