Necroworld

The Necroworld is the hollow cemetery planet tended to by the legendary character known as the Necrobot. He transformed the blasted world into a beautiful garden, filled with holographic statues of every living Cybertronian, which he would switch off when the Cybertronian died. Around the bases of the statues, he planted blue flowers crafted from the residual spark energy of whoever the statue's real-life counterpart was responsible for killing. It is also where "the fortress", the Necrobot's base of operations, can be found.

From space, the planet appears to have two unnamed moons. One, much larger than the other, has its own rings.

Fiction

IDW Generation 1 continuity

The Necrobot's fortress was filled with advanced quantum technology that would let him accurately keep track of the fates of all Cybertronians. It wasn't totally foolproof. In situations where one's death couldn't be confirmed, he would record their name upon a monolith labelled "In Honor of the Disappeared."

The Decepticon Justice Division discovered the planet by complete accident. Since the Necrobot was a neutral party, they ignored him, though Agent 113 attempted to pass the place's coordinates to the Autobots by his usual method.

Years later, the crew of the Lost Light finally dug his bullet out of Swerve's shoulder. It had degraded severely by then, but the coordinates remained intact. With the location in hand, the Lost Light made a detour at the Necroworld to find out what happened to Dominus Ambus, amongst other things. The Not Knowing Their visit inspired him to use their discarded time case to go down the monolith's list of names and bring every 'missing' person to the future to be safe, thus being the reason many went MIA. Do Not Go Gentle

The D.J.D. returned some time after that visit, collaborating with Deathsaurus in order to set a trap for the rogue Megatron and his allies. They murdered Censere for interfering with their plan (his last act being to shield those he'd saved), built a base on the planet, and prepared for their quarry's arrival.How Bright Their Frail Deeds Do Not Go Gentle

When they came, following a signal they thought would lead them toward the source of a psychological attack by the Galactic Council, they accidentally teleported inside the planet, discovering that it was in fact hollow. When they teleported again to the surface, the D.J.D. sprung their trap, forcing the group to take shelter inside the Necrobot's fortress. Deathsaurus's troops besieged the place, but retreated after a few moments with the promise to return at sunset. The Autobots managed to use the flowers' energy to boost the forcefield, giving them a slight edge while they bunkered down and prepared to siege it out. (Megatron attempted to meet Tarn at his statue and surrender, but to no avail.) How Bright Their Frail Deeds The Sun in Flight Your Fierce Tears

In the end, they launched a fierce battle that churned up the soil and narrowly ended in their survival, mainly thanks to the bulk of Decepticons departing in disgust at the D.J.D.'s callous use of their lives. The slumbering missing 'bots woke up shortly into the end, confused by what had gone on. It all seemed done, except for the Galactic Council watching them from orbit and deciding to geobomb the planet! At Close of Day Rage, Rage Do Not Go Gentle

Meanwhile, Nightbeat and Rung had went off to check out the hollow insides of the planet.At Close of Day A bizarre time distortion left them incapable of knowing how long they'd been underground and when examining the planet crust, Rung spotted an inverted version of the Vinvissius Canals on Cybertron. Before the geobomb detonated, an awestruck Rung realized that the hollow Necroworld was the mold that that the metal world of Cybertron was made in! The Dying of the Light Part 6: Do Not Go Gentle

The geobomb did not destroy the Necroworld, however, but transported the whole planet into an alternate universe. Being unable to get off-world, it took the Autobots some time before they realized. A World Misplaced By using Killmaster's wand to envelop the entire planet in a teleportation field, Brainstorm was eventually able to warp the Necroworld back into its own universe. This Machine Kills Fascists

Notes

• The proper name of the Necrobot's planet of operations was not given before More than Meets the Eye #51, where it appears as a caption. The place was previously known only by its rather descriptive appellation since #44.