Tool is a Half-Man, which are bio engineered organisms created to protect the rich and fight wars. Originally serving in an army and fighting in India, Tool eventually breaks free from his conditioning and escapes. He plays the role of a side character in Shipbreaker and a main character in Drowned cities.
Tool mentions in Drowned Cities that he served General Coroa in assaulting India, starting at the Hooghly river and going north. After winning the battle against the Tiger Guard and slaughtering refugees, Tool and his packmates conquer Kolkata. At a different point in time, General Coroa orders Tool's troop to attack Niger. Almost being defeated by the First Claw of Lagos and his Hyena men, Tool wins against them and personally eats the First Claw's heart. Eventually, Tool's packmates, Rip, Blade, and Fear die in battle. Starting in ship breaker, Tool lives on the gulf of mexico as a freelance mercenary and bodyguard. Agreeing to protect Mahila as he journeys north, Tool eventually leaves on his own in Lousiana. After being captured by the United Patriot Front, Tool breaks free, worn down by its squads and a fight with a wild alligator. After finding Nailer and Nita, Tool holds Nita hostage so Nailer can get medicine. He agrees to help Nailer go North to seek some way to escape the warring territories. After freeing mouse from the UPF, Tool decides to stay behind in the land of war to seek his own destiny and territory.