Longinus (ロンギヌス?) is a demon and weapon in the series.
In Christian tradition, the Roman soldier who pierced Jesus in his side with a lance while he was on the Cross. The figure is unnamed in Gospels. 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.
"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.