“Urrgghh... Take note, Seliph! While greed exist in men's hearts...I will return!...You've been warned! Gaaahhh...”
—Loptyr speaking through a dying Julius
Loptyr (ロプトウス Roputousu, romanized Loptous in the Fire Emblem Museum and Loputousu in game) is a major antagonist in Fire Emblem: Genealogy of the Holy War.
Loptyr is a Dark Dragon of the Earth Dragon tribe who fought to oppress humanity in the war with Naga and the Divine Dragons, thousands of years before the events of Genealogy of the Holy War. During the war, he was approached by the bishop Galle and blood-bonded with him to avoid death, granting him great power in return for possession of his body and the bodies of his descendants through the tome named after him.
The now-possessed Galle later returned to his homeland of Jugdral, using his newfound power to form the Lopto Empire. Loptyr would rule the empire for years through Galle's descendants until it was finally overthrown by the Twelve Crusaders after the Miracle of Darna.
Despite this, many people still worshiped Loptyr years later, forming the Lopto Sect and hiding beneath the Yied Shrine in the Yied Desert, The Desert of Death, to evade persecution. Manfroy, leader of the sect, will later devise schemes to manipulate the greed and jealousy of the rulers of the continent, sparking off events which eventually result in Prince Julius being born with major Loptyr blood, allowing Loptyr himself to manipulate and eventually possess him.
Not long after Loptyr fully possesses Julius, both would be slain by Seliph and Julia, who receive the aid of the divine Book of Naga. This essentially proves effective in stopping him from achieving his goal of reviving the Lopto Empire.
"Lopt" was an alternative name for Loki in Norse mythology. During the development of Genealogy of the Holy War, Loptyr was originally planned to be named Loki. "Tyr" was a Norse God of war.