12 years is a long time, long enough time for billions of concepts for The Grand One to create and billions that get scrapped each time. However, after 12 chaotic years, two prototype Digimon were created to form the basis of a new game. Finally, the designs of the Legendary Photondramon and it's nemesis Stellerdramon were born. Several times larger than a football stadium, it favors Defense and HP and takes hits better than Stellerdramon. It was born deep in space when several supernovas occurred at once and formed the Digi-Eggs that would hatch into it's Fresh Stage, which Stellerdramon also shares. It's twin star cannons are placed on it's tail, and when activated, the point forward by extended cables that allow them to take aim at opponents. Compared to Stellerdramon, which formed in icy cold environments in space, Photondramon formed in superheated environments.
It has access to special Ammunition, fittingly dubbed Ammo Silos due to their size, which are placed inside the tail cannon, and while it alone uses them as ammo for a powerful laser attack, the Silos themselves can ALSO be detonated with a special password that is usually linked to human attempts to destroy the Digital World instead. They're popularly used to destroy entire star regions in Grandis's universe by an unnamed alien race, but they're expensive to acquire as production of them had ceased when Stellerdramon and Photondramon both perished for unknown reasons.
Both Stellerdramon and Photondramon make cameo appearances at one point, but are never directly used due to events that happen beforehand. However, it should be noted that the Bombs used to destroy the Earth in the Pilot are actually Ammo Silos that both of them make use of for their tail cannons (Which Fusiondramon also uses a more powerful variant of them). Near the end of Chapter 1, Taro and Solomon discover a base filled with them, but all of them are de-activated permanently, in which Solomon explains to Taro what they are as both of them, and the others afterwards, now know how the Earth was destroyed so easily; Eaglemon had rigged the shut down of the Digital World to instead activate the Ammo Silos planted by Okuwamon, which in turn detonates the entire Earth, before completely vaporizing everything within a few parsec wide range. Despite the mentioning of their Ammunition, neither Digimon are referred to by name during the exposition about them.
Digimon World: Aftermath (Non-Canon)
Photondramon and Stellerdramon are both faced as the final bosses of the main storyline. After defeating both of them at once, both Digimon will DNA Digivolve to form their Omni Level form that serves as the second phase of the final boss fight. Where Brondramon, Cobaldramon, and Jadedramon have cameos prior to the true battle against them, Photondramon and Stellerdramon are first seen as their Champion stage, which is where the digivolution line for the two splits into their Super Ultimate forms, then finally join back together to form a to be revealed Omni stage Digimon. Photondramon is a Defense based Digimon, and is Size Rank 10. Photondramon, like all Digimon above a certain size range, shrink in size when entering tight spaces.
Digimon: Aftermath (Non-Canon)
Prior to Episode 21, all the Digimon that appear are Bandai Digimon, specifically older Bandai Digimon that have been around since the days of Digimon Adventure. Then Episode 21-23 is the three parter "A Star is Born" special. The 21st episode takes place when Marty's wife is giving birth to his son as was going to happen during the series, and taking advantage of the fact Marty will be out of the picture for a while, Eaglemon breaks into Shiramu Inc's secret vault and steals the devices that contain Photondramon and Stellerdramon, but does not use them just yet. Instead, it heads back to it's lair it constructed with the Ultima Gem, a recreation of Infinite Mountain, as the six DigiDestined reach the summit cave and face a lone Ghoulmon, who proceeds to fight the DigiDestined's Digimon until it's defeated, then Eaglemon makes his grand appearance and fights them himself, having used Ghoulmon as a way to weaken them. When Eaglemon appears defeated, he heals himself and releases Photondramon and Stellerdramon, and the first episode of the three parter ends with a cliff hanger.
The second episode ends with the DigiDestined's Digimon being badly defeated by both Super Ultimates, but then when it seems Eaglemon's plan is working, Photondramon turns against Stellerdramon and vice versa. As Eaglemon hopelessly tries to break up the fighting between the two behemoths, the DigiDestined escape. Enraged, Eaglemon chases after the DigiDestined, and during so Photondramon's and Stellerdramon's cannons completely obliterate the barrier between the Digital World and the Real World, causing the Digital World to appear in range of Earth, causing Marty to wonder what the heck is happening. Just then Megaton takes down Eaglemon for the final time, and the episode ends when Duo arrives from her dimension and breaks up the fighting between Photondramon and Stellerdramon with her Super Ultimate Theridramon alongside Omega and both Super Ultimates are ready to face the two, that is, until they DNA Digivolve into their to be revealed Omni Form as the second part ends.
The third part begins with Fusiondramon where the previous episode left off, and Fusiondramon proves to be too much for Omega and Theridramon SU to handle, leaving only one option left, but the DigiDestined and Duo have to find Marty, while Omega decides to hold off Fusiondramon when Megaton joins the fight and digivolves into Millenniummon by aid of a Digivolution Disk he uses on himself, and when the DigiDestined find Marty, he's not in the best of moods as they ran to where he was at only to end up waking up his newborn son and completely angering him, only for his anger to be interrupted upon seeing the Digital World as a planet in the sky. Shouting "OMEGAMON!!!!!!" clear into the heavens, Omega appears before Marty and explains everything he can, until Omega is asked to do the impossible and bring back an old ally, but Omega thought it was long since destroyed. Doing as Marty commands him, Marty brings himself back to the title of The Grand One and summons takes everyone back to the Digital World to see Megaton defeated by Fusiondramon and proceeds to size up Fusiondramon with a revived SuperMechadramon, who with the aid of the six DigiDestined's Digimon, blasts a hole clear through Fusiondramon and destroys the massive Digimon and ends it's rampage. After hearing from Megaton that Eaglemon still lives and is plotting revenge, The Grand One says he can't do anything about Eaglemon since he's got a infant son to help his wife take care of now, so personally leaves it under the new DigiDestined to finish up the work Eaglemon left behind and also seek out Eaglemon and destroy him. Meanwhile, in Rebirth Village in the Digital World, two DigiEggs hatch to reveal the revived Photondramon and Stellerdramon.