Created by Loki as a last defiant act in his "Acts of Vengeance" against Earth's heroes, the Tri-Sentinel is a merger of three prototype Sentinels created by Shaw Industries. Loki programmed the Tri-Sentinel to destroy a nuclear facility on Long Island, the resultant explosion of which would destroy New York City. Spider-Man, who was at this point empowered by the Captain Universe powers, came upon the Tri-Sentinel. Realizing its goal, Spider-Man acted quickly and destroyed it with a beam of energy. After the battle, Spider-Man lost his Captain Universe powers.
Some months later the Life Foundation, an organization who believes in fomenting World War III, rebuilt the Tri-Sentinel in an attempt to replicate the robot for a state-of-the-art security force. Upon its reactivation, the Tri-Sentinel rejected the new programming given it by the Life Foundation and reinstated Loki's original programming. Teaming up with the New Warrior Nova, Spider-Man broke inside the Tri-Sentinel and activated its fail-safe device, which deactivated a shielded box containing Antarctic Vibranium - a synthetic form of Vibranium that is capable of melting metal. The Vibranium began melting the robots' components, but the Tri-Sentinel was determined to repair itself. The Tri-Sentinel eventually overloaded itself with the effort and exploded.
