Disclaimer: I do not own RWBY or Star Wars, this is fan made. No flames, if you do not like then don't read. However, criticism to fix and make it better is appreciated.
It was just an average day for the people of Vale, hunters and huntresses going around protecting the civilians from Grimm, buying dust, and many humans and Faunus alike going about their day. If only they knew what was about to happen. Far, far away from Remnant; clones were turning on their Jedi generals, leading them was the most powerful Jedi turned Sith, Anakin Skywalker. Countless Jedi, droids, and even clones died in order to execute Order 66 properly. Soon after he captured Coruscant, he got a mission from The Emperor, "At the fringes of the galaxy, there's a planet named Remnant, where if their warriors achieve space travel they will destroy the Empire. I command you to go and destroy those warriors until the construction of the Death Star is complete." "It shall be done, my master.", replied the newly knighted Darth Vader.
*Meanwhile, on Remnant*
"Hurry, hurry. RUUUUN!" was heard across the kingdoms as the Grimm, who sensed the oncoming doom, were going on a rampage. Numerous Hunters and Huntresses were sent out to combat the abundances Grimm. At Beacon, the students were sent out to help the villages fight the weaker Grimm, the teachers, however, were battling numerous Hives (the Grimm dragon). In the teams RWBY, CFVY, and JNPR were fighting alongside the White Fang, much to their chagrin.
At the dark side of Remnant, where Salem resides, Salem and her elite were fighting her own Grimm that turned against her. Though, they were having much more trouble as that's where the pools where the Grimm were born from.
Eventually, Ozpin sent a message to all the remaining headmasters and hunters and huntresses to go to Vale as Vale became a hovering island that the Grimm learned to stay away from. Unfortunately, the only team left was team RWBY, CFVY, JNPR, and Adam Taurus. "Hey Adam, good thing you didn't complete level Beacon and Vale in your attack, huh" replied Yang. Adam just sneered at her. "Now now, no fighting as we are the last line of defence against this threat.
Ozpin stated while he sipped on his signature bottomless cup of coffee. "Very well, though this doesn't make us friends, this is only a temporary truce, after this is over we are enemies, understand that humans?" Adam stated with spite.
Blake only looked on with disappointment, she was hoping that this battle would've changed Adam's mind about humanity like RWBY did. "Let's just take a night to rest, the defenses should help hold off the Grimm for the night" stated Ruby trying to end the tension. "yes let's" curtly replied Weiss. "Make no mistake after this you will be the first SCHNEE" Adam stated darkly. All of a sudden RWBY, CFVY, and JNPR got on the defenses, but Adam walked away without another word.
In a separate part of the galaxy, Obi-Wan Kenobi climbed out of the river he was sent into by Commander Cody and the rest of his clone troopers as he was chasing down General Grievous. "Oh man, that was close if the force hadn't warned me I would've been a goner. Though why couldn't they have missed by a few more feet, they would've hit Grievous and helped me", muttered Obi-Wan. As he looked up he saw what looked like a landing pad. "I hope there's a ship up there. "As Obi-Wan force jumped up Grievous was on the top of the landing pad loading up his fighter. As he was putting the last gun in his fighter he heard behind him, "Well, Grievous we keep running into each other I guess". Without turning around Grievous states, "Kenobi". Grievous, still holding the gun, whips around and shoots Kenobi. With decades of experience that only comes from fighting in wars and a little help from the force, Kenobi swings his lightsaber and deflects the blaster bolts. As Kenobi deflects the bolts he slowly creeps closer, cuts of one of Grievous' arms, the one holding the gun. The gun gets sent flying to the edge of the landing pad. In a rage, Grievous launcher Kenobi away, but not before Kenobi Rips Grievous' chest plates apart. By luck or whether stupidity, Grievous launches Kenobi by the gun. Holding on by his fingertips. Kenobi grabs the gun and shoots Grievous in his organs, somehow, igniting them. Eventually Grievous does falls down dead. Kenobi climbs up over the edge of the landing pad and walks to the fighter, Grievous makes a shrilling noise before exploding.
Author Notice: Much of the battle I thought of on the spot as I haven't seen episode three in years. I don't know what the name of the dragon was so I use Hive as a placeholder if you know the name please pm me. Also, Anakin is not yet in his Vader suit as he was sent to Remnant, not Mustafar.