Being an EVO, Rex Salazar can build a variety of machines with his nanites at will. Dubbed as 'builds', Rex's machines can be utilized for transportation or offensive attacks. They are infused with his limbs and add to his enhanced physical condition. Starting off with six original builds, he was granted with the Omega-1 Nanite and gained the ability to build five more.
He could initially operate one machine at a time with minor exceptions; being able to quickly shift between builds. He eventually learned how to employ two builds simultaneously. Unlike the original machines, Rex's Omega-1 machines apply some form of energy-based attacks.
Big fat swordThe big fat sword (also known as the B.F.S.) is a massive orange sword that Rex can transform either arm into. It is one of Rex's most lethal machines. Although it is used offensively to slice through objects, it is can be used to deflect attacks. The big fat sword can also be stabbed into the pavement to provide mobility for Rex and others who hold on to it.
Using a lever on the side of his big fat sword, the top half of the sword will split apart and begin to rotate at a high velocity. This transforms the B.F.S. into the battle saw—a giant orange circular saw that can slice through tough objects. He has used it several times to primarily slice tentacles off from huge EVOs or to cut himself free from tough restraints.
The smack hands are massive orange gauntlets that Rex can transform either arm into (preferably both) to take down larger EVOs. The smack hands give him incredible strength, allowing him to break through obstacles or lift heavy objects. When forming them, he has control over the overall size, length, and flexibility; being able to extend them to reach certain distances. Without the use of his punk busters, Rex can use his smack hands to significantly push himself into the air and ultimately use them to absorb impact when landing. They are also moderately capable of shielding against lasers  and debris,  however, they are weak against acid.  Out of all machines, the smack hands seem to be the only ones that are nerve-sensitive.
This mode allows the smack hands to function as high-powered drills and add additional power behind his strikes. However, Rex can use this to easily drill and travel through underground tunnels. The drills can be used as propellers underwater and effectively launch him at his enemies.
The punk busters are a pair of massive orange super boots with spikes on the soles. They allow Rex to jump hundreds of feet into the air or jump across ten square blocks. He can also use the punk busters to repel powerful EVO enemies or kick through thick metal. In his own words, it feels as if "you were roundhouse kicked by a freight train". The punk busters' stomps are strong enough to cause rising fissures accurate enough to repel his target.
The boogie pack is a jet pack with a pair of wide orange turbine wings. Rex is capable of using it to fly at high speeds; it also gives him a high level of agility. He can launch the twin turbines at an enemy EVO like a bola. He can also shoot two large grappling hooks on the top of both turbines. The Boogie Pack can also propel Rex underwater. He can also use the turbine wings to create compressed air. There is also a limit to how many bodies his boogie pack can transport at once.
The slam cannon is a large orange projectile cannon that Rex can transform either arm into. Similar to a rocket launcher, it is positioned to rest on his shoulder. However, it does not produce its own ammo; instead, a maw on the back end of the slam cannon can extend into the ground and reload solid material for ammunition. It then proceeds to fire the balled material at its target with great force.
The Rex ride is an orange hover motorbike that Rex can form out of his lower legs. The vehicle can drive over any terrain and can go over 200 mph. Despite lacking wheels, the Rex ride is capable of driving up vertical loops and curves. It has a retractable battering ram instead of an engine block and it can be used like a shield to break through trees and various other objects. A helmet build also comes with the Rex ride for protection.
Omega-1 Nanite machines
Blast casterThe blast caster is a machine that consists of a navy-colored, backpack dynamo and a long, black tentacle-like whip that extends from his right arm. It was the first build created with the Omega-1 Nanite. While it does seem to be whip-like, the appendage tends to act as a muscle and can wrap around enemies to grasp them tightly. It can also channel powerful electrical shocks.
FunchucksThe Funchucks are the second build created with the Omega-1 Nanite. They are a pair of giant nunchucks that are attached to both of Rex's arms. He can spin them at an incredible speed and then launch them at once. Rex can also use them to generate a destructive energy pulse, allowing him to shoot light blue bolts of energy at his enemies. Rex can also use the Funchucks as a giant flashlight to see in the dark.
Bad AxesThe Bad Axes are the third build created with the Omega-1 Nanite. They are a pair of large blue axes that Rex builds with his hands. The axes are so powerful that they are capable of easily slicing Providence fighter jets with one slice.
Block PartyThe Block Party are a pair of navy blue colored metal gauntlets. They can generate medium-sized blue circular energy shields that are made of highly energized atoms. The energy shields are capable of withstanding an extensive amount of damage before shattering like glass. The shields can block laser and other energy type attacks. The Block Party can also generate a large energy dome force field.
The Sky Slyder is a blue glowing machine that Rex builds with his lower legs. It is similar to a regular surfing board, except it can fly at high speeds in midair. Rex initially had trouble creating the Sky Slyder, but he successfully built it later on.
The Upgrade suit is the form that Rex takes by merging with Upgrade. Powered by alien technology, the Upgrade suit enhances Rex's builds to levels far beyond known technology on Earth.
The Alien Excalibur, the upgraded version of the Big Fat Sword, is an alien-tech enhanced machine blade. It is considerably larger and more impressive than the normal B.F.S. Its cutting power is also much greater than the original B.F.S., as it was able to easily cleave through the massive and durable Alpha-Omega in a single slash.
The Power Fists, the upgraded version of the Smack Hands, are alien tech enhanced machine fists. They are much larger and stronger and have spikes. The fists can be fired off as projectile missiles. They are far stronger than the original versions, easily knocking back the massive Alpha-Omega with a single hit.
The Hyper Jet, the upgraded version of the Boogie Pack, is an alien-tech enhanced machine jet pack. Its speed and maneuverability greatly exceed that of its normal form, allowing Rex to easily avoid a barrage of attacks from Alpha-Omega. Also, as a form of attack it can launch a pair of powerful rockets from the turbines, which was strong enough to stun Alpha-Omega temporarily.
The Blast Launcher, the upgraded version of the Slam Cannon, is an alien tech enhanced machine cannon. Rather than loading ammo, the Blast Launcher produces six extremely powerful missiles. These missiles pack immense explosive force; a single shot from the Blast Launcher knocked Alpha-Omega through a large building.
The Swift Rocket, the upgraded version of the Rex Ride, is an alien-tech enhanced transport vehicle. It is considerably faster than the original Rex Ride, capable of speeds over 1,000 mph.
Full EVO form
A young Rex demonstrated the use of a giant bio-mechanical form that had most of Rex's current builds, including a version of the B.F.S. on one arm, Punk Busters for legs, Slam Cannons on both shoulders, and a Smack Hand on the other arm. It also had a chest plate that slightly resembled the Smack Hands, shoulder pads that resembled the turbines of the Boogie Pack, and the helmet from when he uses the Rex Ride.
While in this large and imposing form, Rex demonstrated typical EVO-on-the-loose behavior, and after reverting to his human form, he lost his memories. Rex partially transformed into this form when he was about to be dissected by Dr. Fell, meaning this may be a defense mechanism. He was also about to return to this form when he was trying to regain his memory with Caesar's ineffective memory machine.
When exploring the underground chambers in Abysus, a colored drawing, presumably made by Rex himself, has some resemblance to this form. There is not any indication that this was inspired by his form, or that the idea of it inspired the form itself.
Full Omega-EVO form
As a complete armor is activated by the Omega-1 Nanite, it is a powerful robotic body. Rex activated the form to defeat the Consortium. It appears that the robotic armor has fiery blue flames as hair and blue colored armor. Unlike his other Full-EVO form, Rex is in control of himself.
Reversal EVO form
When Rex came in contact with Component 326, he transformed into a smaller version of his full EVO form. While he is in this form he has his Smack Hands, a B.F.S. and the Punk Busters. He also has green glowing eyes.
- The Smack Hands were the first machines to appear in the series.
- In FusionFall, the Rex Nano's B.F.S. attack is called "Big Freakin' Sword".
- The Blast Caster is the first build created with the Omega-1 Nanite and it is also the only Omega-1 machine to appear in season 1.
- The Upgrade Suit is the only build created with the help of another character.
- The Boogie Pack may be a nod to the original M. Rex comic book series, in which Rex voiced his desire to own "a jet pack with twin turbos", like his favorite hero - "Captain Blade Pierce".
- Rex showed enough dexterity with the Battle Saw to carve a statue of himself from a stalagmite.
- The Punk Busters are the only original machine not used with the Upgrade Suit in "Heroes United".
- The Sky Slyder is the only accessible machine that did not appear in "Ben 10/Generator Rex: Heroes United".
- Rex tried to create the Funchucks several times, but only succeeded when his bio-metrics were up and he needed to save Noah.
- Almost all of Rex Salazar's machines from Season One have a primarily orange color scheme. All the new machines he builds in Season Two have a primarily blue color scheme. The blue represents that these builds were made by the Omega-1 Nanite that Rex received from Dr. Rylander.
- All the machines Rex Salazar builds with the help of Upgrade have a primary black and green striped color scheme.
- For reasons unknown to Rex, he couldn't build more than one machine at a time. Thanks to Six's motivation, he unblocked this mental barrier, allowing him to build two machines at the same time.
- Rex's first "double up" was a set containing the Rex Ride and the Slam Cannon in "Crash and Burn".
- According to Dr. Holiday, Rex loses his builds in a relatively painless way.
- Most of the original builds seem to have a second mode/use. (E.g., the Smack Hands have the combat drill mode, the BFS has the battle saw mode, the Rex Ride has the battering ram mode, etc.)
- The Omega builds on the other hand only have 1 mode, mostly to make up for their increase in power.
- In Generator Rex: Agent of Providence, Rex can spin the Bad Axes at an incredible speed, slicing his enemies.
- In the early design, the Sky Slyder was referred to as the Skyslider, Sky Slicer, and Sky Board.
- Rex has not used the original and Omega-1 machines together.
- When Black Knight absorbed a Meta-Nanite her machines were identical to Rex's but with a purple color scheme.
- Caesar once theorized that Rex's unique powers might stem from the mechanical Meta-Nanite hidden in his body.