Disgustedorite's SU-ST Crossover AU

Disgustedorite's SU-ST Crossover AU is an AU created by Disgustedorite, in which the events of Steven Universe (modified based on her own personal AU) and the TV franchise Star Trek happen in the same universe or multiverse. It is a sub-AU of Disgustedorite's personal AU. Only the prime Star Trek universe--that is, before the reboot in 2009--applies to this AU; the events of Star Trek Online are also considered canon.

Description
Within this AU, Steven Universe and Star Trek both happened. While the details may be harder to work out, Gemkind had an influence on several planets in this galaxy other than Earth, being known to have encountered countless races. While the majority of Gems left behind after the rest of their species fled the galaxy are concentrated on Earth, a few are known to have stayed on other planets brought in from the Star Trek universe, such as Talax, Remus, and Ferenginar.

As this is a sub-AU of Disgustedorite's Personal AU, all of DD's gemsonas do exist within this universe; however, the only one of any significance is Mali "Grossular" Garnet, who served as a backup power source on board the Maquis ship that eventually had its crew merged with that of the starship USS Voyager after becoming lost in the Delta Quadrant in the 24th century. After the crews were merged, she worked in Engineering and, briefly, as the on-board fusion expert.

Changes to Established Star Trek Canon
In addition to vague Gem influence throughout the galaxy, various characters and episodes are altered to integrate Gems into the story. A few of these changes are practical or necessary, but the majority are just for fun.

Modified Characters

 * Neelix from the Star Trek: Voyager series is part Gem. It's from a distant ancestor who was a Quartz; as the gemstone wasn't passed on beyond the initial hybrid, the Gem genes became greatly diluted, so Neelix has no Gem powers...aside from the ability to fuse, apparently.
 * Tuvix, also from Star Trek: Voyager, is changed to a tall, more Steven Universe-like fusion with extra arms and extra eyes.

Modified Episodes

 * The Star Trek: Voyager episode Tuvix is modified so that instead of the fusion being caused by plants and transporter malfunction...it's caused by Neelix, who is apparently part Gem, actually accidentally initiating fusion with Tuvok while being transported. And there was only one Gem on board who might be able to explain this and help the fusion stop. Most importantly, the episode doesn't end with the death of Tuvix, as he lives on in Tuvok and Neelix and can still be formed again.
 * A handful of future episodes are also altered from here so that Tuvix does form again for various reasons, but without staying as Tuvix for the entire episode.
 * The Star Trek: The Original Series episode Patterns of Force does not happen, as World War II and the holocaust did not happen in Steven Universe's universe and this was carried over.
 * Further episodes with references to Nazism are modified or removed as well, and they will be listed as I am reminded of them.

Changes to Established Steven Universe Canon
As the events of Star Trek mostly pertain to the future and Steven Universe mostly pertains to the past and present, there are naturally far fewer changes than there are to Star Trek canon. The current status of some of the canon Gems is included here as well.

Modified Characters
(to be written)

Modified Episodes
(to be written)

Mirror Universe

 * Steven's Knife

Status of Canon Gems
Other Gems on Earth have not been decided yet. I'll update this as the show goes on and we know more about them.
 * In the 22nd century, Steven becomes a diplomat and a traveling magic doctor, helping people all across the known galaxy. Doctors are baffled by his lack of aging. In the 25th century, he spends time helping the surviving Romulans
 * Lapis becomes a traveler who just kinda follows Steven. She sets out around the same time he does.
 * Garnet stays on Earth, continuing to protect it through the 25th century.
 * Amethyst generally stays within a few light-years of Earth after humans develop warp power, as she doesn't like to be away from home. During the 24th century, she gets dragged off to the edge of Federation territory against her will; however, she returns to Earth soon afterwards. In the 25th century, she continues to stay near her home planet.
 * Pearl started running around the galaxy on her own the moment the warp drive was invented. She kept in contact with the other Crystal Gems and her whereabouts were easy to look up on Federation records, as she often took public transports and even rode big-name starships like Enterprise. However, in the late 24th century, she disappeared somewhere in what was formerly Romulan space (the empire was disintegrated by their home planets' destruction in 2387). Her whereabouts are still unknown in the 25th century.
 * Peridot stayed at the barn with Lapis until Lapis decided to travel with Steven in the 22nd century. After that, through a series of surprisingly comical events, Peridot ended up serving on board the original Enterprise (seen in Star Trek: Enterprise), where she was one of the few non-humans on board. She worked in the Engineering department there, and on every Enterprise after that.
 * She got into an argument with Scottie once in the 23rd century. It was funny.

Changes Directly Pertaining to Both Shows
Here's where the real crossover goodness comes in!

Changes to Technology

 * In the 22nd century, humans, being paranoid about transporter accidents, actually abandon their matter stream based transporters in favor of a new technology based on warp pads left on Earth by Gems. The range limit is still the same.

Changes to Events

 * The Crystal Gems failed to stop the Eugenics War, but they did prevent the majority of the deaths. They determined that the Augments were a threat to life on Earth, even though they were living beings, because they killed so many people and the Augments were even threatening the Crystal Gems themselves. They determined that it'd be in the world's best interest if they destroyed or incapacitated them.
 * All of this happened before Steven was born; Rose Quartz felt sorrow for all the people who died in the war, even the Augments she knew she had to help destroy.
 * Greg had already met the Crystal Gems when the Eugenics War happened. He did not participate.
 * Gems living on Earth, specifically formerly corrupted Gems, assisted in all major battles with the Borg. Gems could not be assimilated, making them extremely valuable for all types of situations involving the Borg.

Changes to Prejudices

 * Due to people across the galaxy already being familiar with shapeshifting Gems, prejudice against Changelings and other shapeshifting races is based on them being able to shapeshift perfectly and fool even the trained eye, rather than on them just being shapeshifters at all.
 * However, during the Dominion War, prejudice against Gems did briefly occur due to paranoia. In addition, some innocent Gems were also attacked after being seen shapeshifting by people who were less familiar with the species and mistook them for Changelings.
 * Paranoia-based prejudice against Gems became worse when a Changeling actually shapeshifted into a Gem; before that point, it hadn't really occurred to anyone that a changeling could pretend to be a Gem.
 * As Gem blood is weird to deal with, the easiest way to determine if a Gem is actually a changeling in disguise is to cut her in half. This obviously didn't fly too well with Gems living in any areas affected by the Dominion War.

Steven Universe
(to be written)

Star Trek

 * (to be named): A semi-filler episode of Star Trek: Deep Space Nine. The A plot involves illegal weapons transport relevant to the current plot; and the B plot involves Odo having to catch a very frightened Amethyst who had been mistaken for a jewel after being poofed, being illegally passed along to many different buyers across the Alpha Quadrant before ending up on the station where she finally had enough room to reform. Season number not decided; will have to rewatch Deep Space Nine to decide, though I think I have a basic idea.

Other Changes
(to be written)

Trivia

 * This AU us unneeded but eh