Photon Grenades, alternatively known as S-Mine Detonators, were a type of detonator utilized by the Eighth Brother, who was an Imperial Inquisitor. These compact detonators were part of his equipment on numerous occasions, notably during the early years of the Imperial Era and during a quest to locate the former Sith Lord Maul on the planet of Malachor in 3 BBY. When the Eighth Brother encountered the Jedi Kanan Jarrus, his apprentice Ezra Bridger, and the former Jedi Ahsoka Tano on Malachor, the Inquisitor, finding himself outnumbered, hurled three S-Mine Detonators towards them, creating an opportunity for his own escape.
These disk-shaped explosives, Grenades also referred to as Photon Detonators or S-Mine, were compact and carried by the Eighth Brother, an Imperial Inquisitor. Sporting a Gray and black color scheme, these detonators could be affixed to a belt for ease of access. Typically, the Eighth Brother would carry multiple units. When armed, the detonators emitted a red glow, and upon detonation, they produced an explosion of various colors.
During 19 BBY, the Eighth Brother was seen wearing these detonators on his uniform while training alongside fellow Inquisitors on the planet Coruscant. He was later observed wearing them at the Inquisitorius Headquarters on Coruscant, subsequent to a successful Jedi hunt conducted by the Inquisitors in 14 BBY. In 3 BBY, the Eighth Brother transported several S-Mine Detonators to Malachor as he pursued the former Sith Lord Maul. Upon encountering the Jedi Kanan Jarrus, his apprentice Ezra Bridger, and the former Jedi Ahsoka Tano, the Eighth Brother launched three S-Mine Detonators at the advancing group. The resulting explosions caused the ground beneath Bridger to collapse, leading to his fall and affording the outnumbered Inquisitor with a chance to escape.
Later, the Sith Lord Darth Sidious included illustrations of S-Mine Detonators in a visualization of the Inquisitors, including the Eighth Brother, within The Secrets of the Sith, a book authored by him prior to his death during the Battle of Exegol in 35 ABY.
The initial appearance of S-Mine Detonators occurred in the first part of the two-part episode titled "Twilight of the Apprentice," which served as the finale for the second season of the animated TV show Star Wars Rebels. It was broadcast on March 30, 2016. These detonators were initially depicted in the Season Two mid-season trailer, which was released on January 15 of the same year, and their identification was provided in the episode's official guide. Concept artwork for "Twilight of the Apprentice" showcasing the S-Mine Detonators, dated April 21, 2015, was created by senior concept designer Amy Beth Christenson.
Subsequently, S-Mine Detonators were identified as Photon Grenades in a pair of separate forum posts made by EA Capital Games on March 23, 2022. These posts served as previews for their incorporation into the video game Star Wars: Galaxy of Heroes, which had its original release on November 24, 2015. The Eighth Brother, along with his Photon Grenades, were integrated into the game on March 24, 2022. The game developers for Galaxy of Heroes intentionally crafted the Photon Grenades ability's name and animation to mirror the Eighth Brother's scenes in "Twilight of the Apprentice."