The Soulreaper axe is a two-handed axe that requires 80 Attack and Strength to wield. It is created by combining four untradeable components, obtained as drops from The Leviathan, The Whisperer, Vardorvis, and Duke Sucellus, alongside 2,000 blood runes.

The axe has a passive on-attack effect, which damages the wielder 8 Hitpoints, and grants a "Soul stack" for every attack they make. As long as a player is not at the maximum amount of stacks (5) and has more than 8 hitpoints, they will take damage and receive one stack of this effect. Each Soul stack provides a 6% boost to a player's Strength Level, up to a maximum of +30% at five stacks. These stacks can be used for the Special Attack Behead, or lost at the rate of one per 20 ticks (12 seconds) of the player not attacking. The player is healed for 8 hitpoints for each Soul stack lost over time or otherwise used through the special attack.

In circumstances where all five Soul stacks are consistently applied to the player, this weapon can deal substantially more damage than other single-target two-handed weapons.

Despite being made from items dropped by prominent Zarosians, the item itself does not grant god protection towards Zarosian NPCs in the God Wars Dungeon.