Endurph is an Exif, a species of extraterrestrial humanoids, who holds the dual roles of a cardinal in the Exif religious order and a lieutenant general in the United Earth military aboard the flagship Aratrum. His physical appearance is typical of his kind, characterized by very pale skin, light blonde hair, and pointed ears set higher on the head than a human's. With a weathered look and a prominent brow, he appears older than his close ally Metphies. His age is given as 105 years, which is roughly equivalent to a 50-year-old human due to the longevity of his species.

At the beginning of the conflict against Godzilla, Endurph presents himself as a reserved and pragmatic strategist. He is one of the first to support the anti-Godzilla thesis written by the human protagonist Haruo Sakaki, endorsing the plan to return to Earth and exterminate the monster. In his capacity as a high-ranking officer, he participates in critical military briefings, calculating the range of Godzilla Earth's atomic breath and advising the Aratrum's captain on tactical decisions. When a landing party is attacked and contact is lost, Endurph argues against an immediate retreat, successfully advocating for a limited 48-hour window to search for survivors on the planet's surface. He also utilizes Exif technology, such as the subspace navigation system Gematron, and makes predictions that prove accurate, such as the exchange of voices that signals the return of a damaged landing craft.

Beneath this composed exterior, however, lies a deep and ultimately fanatical religious conviction. Endurph is frequently shown leading small groups of soldiers in prayer, invoking divine mercy and speaking of a promised day when their god would descend. This duality is central to his character; he is both a calculating military man and a zealot. The Exif homeworld was destroyed by the extradimensional entity King Ghidorah 100,000 years prior to the events of the film. Following this catastrophe, the surviving Exif came to worship Ghidorah as a god and adopted a nihilistic mission to convert other civilizations and offer them up to their deity.

As the human and Bilusaludo forces fail to defeat Godzilla using the mechanical city of Mechagodzilla, Endurph's religious extremism comes to the forefront. Disillusioned with conventional military strategy, he shifts his allegiance fully toward his faith. While he officially leads the Exif contingent on the Aratrum, he defers to the authority of Archbishop Metphies, whom he recognizes as the Exif oracle. Through telepathic communication with Metphies, Endurph agrees to proceed with the ritual to summon Ghidorah, believing that only divine intervention can now defeat Godzilla.

In the final stages of the conflict, Endurph sheds his reserved nature entirely. He personally leads his followers in ritualistic chants to open a dimensional portal and summon King Ghidorah. As the chaos of Ghidorah's manifestation begins to tear the Aratrum apart with gravitational forces, Endurph does not flee. Instead, he remains transfixed, displaying uncharacteristic maniacal laughter and ecstatic devotion. His fate is sealed as the ship is engulfed in flames and destroyed, with Endurph perishing in the cataclysm, his final moments a stark contrast to the calculating officer seen earlier. This transformation from a composed strategic thinker to an apocalyptic fanatic defines his role, serving as a key instrument in the Exif plan to sacrifice humanity to the monster they worship as a god.