Saint Longinus was a Blind Roman Centurion and Soldier that pierced the side of Jesus Christ with a lance which would become the Lance of Longinus and had converted to Christianity and became a Saint under the name of God.
In Christian tradition, the Roman soldier who pierced Jesus in his side with a lance while he was on the Cross. Some of Jesus's blood fell upon his eyes and he was healed. Upon this miracle Longinus believed in Jesus. The Longinus legend further identifies this soldier as the centurion present at the Crucifixion, who testified, "In truth this man was son of God". Longinus' legend grew over the years to the point that he was said to have converted to Christianity after the Crucifixion, and he is traditionally venerated as a saint in the Catholic Church and several other Christian communions. The figure is unnamed in Gospels.
The Lance of Longinus, also known as Spear of Longinus, Spear of Destiny, or simply Longinus, is a powerful holy relic and weapon, which was created when a roman centurion was used to pierce the side of Jesus Christ in order to prove that he is dead while crucified. The lance is called in Christianity the "Holy Lance" and the story is related in the Gospel of John during the Crucifixion. This act is said to have created the last of the Five Holy Wounds of Christ.
"A Roman soldier who used his spear to pierce the body of Jesus Christ as he was on the cross. According to some legends, the blood of Christ cured Longinus of his blindness. Afterwards, he reconciled his ways and became canonized. Obtaining the Holy Lance of Longinus grants one power to become the ruler of the world, but losing it means your doom."
—Devil Summoner: Soul Hackers 3DS Compendium
Longinus can be obtained if Zeed is level 70 or higher and fused with Metatron during a new moon.
Longinus is a special fusion unlocked by one of Elizabeth's requests. He can be fused at level 55 with Tam Lin and Kartikeya, two other mythological figures known for using polearms. Longinus' skills, Power Charge and Vorpal Blade, make him a powerful physical persona for the mid-game.