Summary. In Star Wars, Starkiller Base was a weapon used by the First Order to destroy multiple planets at once. It destroyed the five planets, Hosnian Prime, Hosnian, Raysho, Cardota, and Courtsilius.
Even if one were to look only at the portion of the planet that is used as a base of operations, Starkiller Base is still said to be roughly two times larger than the Death Star at a minimum. Rather than wiping out a single planet, this bulky but slow superweapon was capable of destroying whole star systems.
Starkiller Base in The Force Awakens took out the entire Hosnian System, with an estimated 155 billion people killed, a 99.99% comparable. There's an eye for an eye, and then there are the optics of this, an eye for an entire human being.
Lord Starkiller is an antagonist in an alternate Star Wars timeline in which Darth Vader is defeated and killed by his former apprentice Galen Marek, code named Starkiller.
He is pretty powerful, definitely up at an A tier level of ability. He has faced quite a few potent Jedi masters. If memory serves, the most powerful person he beat outright was Shaak Ti. He did technically beat Vader, but he used lightning and then damaged his suit with a hurled piece of debris that exploded.
Naboo was among the first worlds to be attacked. Despite the planet sustaining heavy losses, Operation: Cinder was foiled before Naboo could be destroyed. After that, however, little is known about Naboo, other than it was saved from the First Order after Star Wars: The Rise of Skywalker.
Out of the 2 billion inhabitants on Alderaan - with the modern-day populations of China and India having about 2.8 billion people combined - about 60,000 survived the destruction of the planet due to being outside of its star system at the time.
Supreme Chancellor Palpatine, with assistance from the Geonosians, had plotted to build the first dreaded Death Star -- a weapon unlike anything the galaxy had ever seen.
Out of Alderaan's two billion inhabitants, roughly 60,000 survived the destruction of the world because they were outside of its star system at the time. The death of so many sentients sent shock waves through the Force, weakening those who were able to feel them.
When the First Order annihilated the New Republic in J.J. Abrams' The Force Awakens (2015), Starkiller Base blew up the galactic capital Hosnian Prime rather than Coruscant. Lucasfilm executive Hidalgo was recently asked on Twitter about the decision to make Hosnian Prime the capital in Episode VII.
The Hosnian system was destroyed by Starkiller Base during the Hosnian Cataclysm starting a war between the First Order and the Resistance. In 28 ABY, the system was home to the New Republic Senate on Hosnian Prime.
A notable Jar'Kai master was the Priapulin Jedi Master Skwelli, who carried six lightsabers. He was renowned for his skill in his era, and recordings of his fighting form were considered a wonder to behold.
The wiki page for starwars.fandom.com/wiki/Starkiller_Base says it's 660 km wide—tiny for a planet, but curiously the same size as starwars.fandom.com/wiki/Ilum...
During the match, Luke remarks that Starkiller was making him angry, and when Luke is then defeated by Starkiller, who mocks him on destroying him as he "destroyed his father", Luke screams in anger and falls to the the dark side as Fallen Luke.
It is also outright stated that Sidious was feigning weakness to goad Starkiller into striking him down and to turn him to the Dark Side. He didn't beat Sidious. He even went oneness and then died to Sidious.
In the real universe, Luke became a Jedi, Redeemed his father, and lived happily ever after. BUT, in the Ultimate Sith Edition, he fought Lord Starkiller on Hoth and turned to the Dark Side.
Starkiller Base fires its planet-shattering beam. Under orders from Snoke, Hux prepared the Starkiller weapon to fire against the Hosnian system in the Core Worlds, the capital of the New Republic.
While Vader had his weaknesses, including vulnerability to electricity, characters like Emperor Palpatine, Mace Windu, Yoda, and Obi-Wan Kenobi all had the potential to defeat him in battle.
