The toktz-xil-ak, also known as the obsidian splitsword or obby sword, requires an Attack level of 60 to wield. It has a shortsword attack style, with bonuses similar to a rune longsword, making it the second strongest shortsword.
When correctly used, the obsidian sword is one of the best weapons used for training Strength, especially for those who do not want to complete the master quest Monkey Madness I for use of the dragon scimitar.
When a Berserker necklace is equipped, this weapon gains a 20% damage boost. It is also affected by the Obsidian armour (helmet, platebody and platelegs) which will increase the melee attack and melee strength by 10%. The damage bonus does stack with the Berserker necklace.