The Steward is the secondary antagonist of the Cartoon Network show, Infinity Train.
The Steward is a sentient octopus-like robot created by the Conductor as surveillance for the Infinity Train. She is tasked with finding One-One and either bringing him to her alive or kill him once she finds him on the spot so the Conductor can keep control of the train forever. To do such task she goes to all the train cars and purposefully sabotages them in hopes of finding One-One, which she never does for 30 years. One day, she finds him in the possession of Tulip, a young girl who got lost on her way to Oshkosh, Wisconsin, and proceeds to report to the Conductor about One-One's whereabouts, and is assigned to kill him and his friends, but ultimately fails due to Atticus ripping her apart.
The Steward was presumably created sometime after the Conductor overthrew One-One and threw him out of the engine of the train. She made her specifically to hunt One-One down and either bring him to her alive or have the Steward kill him on the spot. She sends her out to the train and she starts looking for him for years, never finding him. In the process she destroys or sabotages many cars, presumably killing many or all inhabitants residing in said cars as a result of her actions. Over time, she makes an alliance with a sentient cat that cons people for a living in hopes of finding One-One faster. She then proceeded to a place in the train called Corginia and starts to sabotage it by yanking out orbs looking very similar to One-One, tossing them aside when she realizes they're not him. This undoes many effects on the kingdom and soon it is awash with tsunamis and floods, sinking many buildings and killing many dogs within them. Unbeknownst to her, the cat whom she made an alliance with actually got a hold of One-One and was presumably taking it to her when Tulip wrecks the craft to get him back, leaving her stranded. She encounters Tulip while still yanking out orbs, with her finding out that she was the "shadow monster" Atticus warned her about. As the trio notice the effects the Steward is having with her recklessness, they proceed to sneak out the door to avoid her. However, One-One pops out of the bush they're hiding in and exposes them, causing the Steward to fire bullets at them. Atticus then charges at her, but she makes short work of him by smacking him aside hard. She then focuses on Tulip, and proceeds to tell her "RETURN TO YOUR SEAT!!!" as she drags her towards her to presumably return her to her original car or kill her for interfering, when Atticus is seen reverting all changes to return Corginia to normal. She didn't care, and decides to strangle Tulip when One-One suddenly emerges from her pack doing a weird dance routine. Stunned, the Steward stops her attack, allowing Tulip to slam the door on her and escape, but was horrified to see her face underneath the mask. The Steward didn't mind, and proceeds to shut the door and rip a hole in the ceiling to make her escape, racing towards the engine to report to the Conductor.
Once she learned about the news, the Conductor has the Steward to go back and capture One-One and kill the others. The Steward then moves the cat's car towards the engine and tells her about a plan that she's making to capture One-One and the cat decides to go through with it. The Steward takes out a tape containing Tulip's memories (which was presumably made when the Conductor knocked her unconscious) and gave it to the cat, instructing her to trap Tulip in there and take One-One and give it to her so she can take it to the Conductor. She then sends the cat towards Tulip's exact location replacing the next car. The plan backfired after Tulip manages to come to terms with her past and realizes that it was a setup for a death trap and the cat intended to kill her. She then kicks her aside and leaves with Atticus and One-One in tow. The Steward then sees that her plan failed and became furious but was confronted by the Conductor over the cat's failure, distracting them long enough to not see the cat hide a memory tape into her vest. The Conductor then moves the cat's car towards the engine and the Steward asks for Tulip and One-One's whereabouts, to which the cat replied that they were gone. Furious, the Conductor decides to kill her for her inability to capture/kill them, but then changes her mind when the cat declares that she's the only one that can help them. She then leaves her to the Steward, who demolishes the cat's car and abducts her.
With the cat captive, the Steward forces her to track down Tulip and One-One, eventually finding them at a fast-food playground-like train car. She sees Tulip, One-One, and Atticus playing in the jungle gym and decides to ambush them to avoid any foul-ups. However, her tentacles are seen by Tulip, and she realizes the Steward has tracked her down. She warns her friends and they try to escape, however a water toy falls into the Steward's tentacles, her crushing it. She realizes the trio are trying to escape and brings the whole jungle gym crashing down, seriously injuring Tulip and One-One being scattered to another slide. The Steward sends the cat to go after him, and once she jumps in the slide, she shoots it to smithereens, presumably killing the cat and One-One altogether. The Conductor then appears and taunts Tulip for her failure, then starts accusing her of rejecting the traps she perceived as "gifts", including the setup with her memories, revealing her role in them. She sees the ruins of the car, and blames Tulip for her friend's deaths. Just then, Atticus leaps out of the wreckage and tries to attack the Conductor, but she grabs him and shoots him in the head, killing him, then tossing his corpse at Tulip. The corpse then transforms to a Ghom and starts to drain Tulip but One-One emerges from the wreckage as well, making the Steward destroy the entire train car and leaves with the Conductor back to the engine.
Back at the engine, she is seen resting while the Conductor is still hard at work making a train car, so she's mostly away from the battle that was taking place, until she was summoned to break the Conductor from her trance after Tulip trapped her in her own memory tape. The Steward destroys the tape, snapping the Conductor back to reality. Furious, the Conductor orders the Steward to kill Tulip and One-One but a Ghom-ized Atticus attacks her instead, forcing the Conductor to chase Tulip herself. In the meantime, One-One sneaks by unnoticed and finds the motherboard and is immediately attracted to it. The Ghom gains the upper hand, about to rip the Steward to shreds when Tulip shoots him, transforming him back to Atticus, giving the Steward the advantage and smack him into the wall, killing him again. However, she is too late once she sees One-One in the train's motherboard and tries to pry him off, but is pushed back. Atticus then leaps out of the wreckage (presumably revived by One-One) and proceeds to rip her apart, avenging his subjects' deaths and Corginia's damages at her hands.
The Steward is an octopus-like robot that has many tentacles that she uses as hands and feet. She wears a mask to hide her face, which is only 2 flamethrowers and gears, as well as rounds of ammunition stored behind her eyes to shoot at things. Despite her fragile-like octopod-like appearance, she is immensely strong and agile, shown when she gets violent, like when she destroys the cat's car with little effort. She can toss creatures aside with a simple smack and can lift humans effortlessly. She can also use her tentacles to strangle or asphyxiate living beings to death, seen when she grabs Tulip by the leg and drags her towards her to either kill or send her back to her original car.