As the main antagonist of the Enterprising Engines, Sir Frederick Aura is ruthless, uncaring, and cruel, and bad things come to anyone who meets him. Aura has been known to intimidate people into making alliances with him under the threat of death, and has even outright killed or attempted to kill engines and people in his way. Since Aura operates from the shadows, very few know of his true maniacal nature, but those who do often disappear under mysterious circumstances, as Aura believes there must be "no loose ends" that could affect his mysterious plan.
In Munitions, Aura refers to the engines as "industrious, spineless, worthless artifacts." It is presumed that they are victims of his scheme.
In Munitions, the diesels work with him to set The Ministry of Defense Complex into a frenzy. The two shuttle Aura and Richards to the complex and wait for them by the exit. After Aura and Richards fire upon Paxton's fuel train and set the complex ablaze, 'Arry and Bert then help the two escape the complex by bringing them back to The Sodor Ironworks. Later, when Aura is threatening Captain Grant two months after the incident, the two are in the Ironworks working but do nothing to stop Aura from killing Grant.Munitions.
When Aura and his hitman attack the complex in the episode, Aura appears to have no problem leaving Grant to die. However, as Aura and the hitman are escaping aboard 'Arry and Bert, Grant spots Aura and does not recognize him, wondering who he is. Darren hurries him along, and Grant appears to give no further thought to Aura. However, Aura believes that now that Grant has seen him, he is a "loose end" that needs to be tied up.
A few months later, Grant receives a sympathetic letter in the mail from an anonymous sender, asking for a chance to "exchange war stories." Grant is unsuspicious, and happily attends, but is kidnapped by none other than Aura, who vows to end his life because he is a loose end in his scheme. The two briefly spar but Grant is overpowered by this sinister foe. Aura casually reveals his entire plot to Grant and reveals his hate of the railway. Grant tells him that his plan had failed, but Aura, angry, kicks him down some stairs and states that it was only the first clash of blades and that he had predicted the outcome. He then impales Grant with his sword, mockingly telling him that it was an honor working with him.
Aura does not approve of Carlo's rude behavior and says he will fix it someday. Carlo is implied to be reluctantly smuggling arms and weapons from his "lumber business" to aid in his Aura's aims, for a price, of course.
In an attempt to send a message to Walter Sliggs, Aura has Ricky Mason and Walter Richards sabotage D261 and D199. The two smash into The Mine Junction, just missing Sliggs's refinery. Aura obviously did not care about the well-being of the two diesels and views them as objects to further his own end.
In an attempt to send a message to Walter Sliggs, Aura has Ricky Mason and Walter Richards sabotage D199 and D261. The two smash into The Mine Junction, just missing Sliggs's refinery. Aura obviously did not care about the well-being of the two diesels and views them as objects to further his own end.
While Aura and Darren never directly interact, it is Aura's actions that lead to Darren's death in Aura of Menace.
In Munitions, when Aura is spotted by Captain Grant, Darren hurries him along, believing that the care of General Zen is more important than Aura. Later, the group comes across a trench, which was caused by an explosion Aura planned.
In Munitions, Aura's entire plan revolved around framing and/or killing Zen. Aura and Richards fired upon Paxton's fuel tankers in an attempt to frame Zen for his carelessness. Zen was injured in the following chaos, and Aura blew up a bridge that would allow The Thin Controller, Darren, Captain Grant, Derek's driver, and several soldiers to bring Zen to safety, mockingly bidding him farewell. After the incident, Aura visited the hospital Zen was being treated at and undermined his control, presumably taking control of the military command of the aftermath of the blaze.
Sir Frederick Aura's hitman is exceedingly loyal to him, and follows his commands to the letter without question.
In Munitions, he accompanied Aura to The Ministry of Defense Complex and fired the shot that lit Paxton's tankers on fire, setting the complex into chaos. He then escaped with Aura onboard 'Arry and Bert.
In Aura of Menace, he and Ricky Mason sabotaged D199 and D261 under Aura's orders. The two also later held up a signalman so the two diesels would crash into Walter Sliggs's refinery. After this, the two presumably killed the signalman.
In Samson, BoCo, and the Man in the Hills, the Hitman was dispatched by Aura to silence the two henchmen who carelessly attracted attention when they blew up the Man in the Hills carving near Crovan's Gate Mine. Aura then strictly reminds him to find Proteus' lamp.
In Culdee Fell, the Hitman is revealed to be Walter Richards, the controller of the Mountain Railway. Throughout the episode's second half, it is revealed that his loyalty to Aura may in fact be motivated by a desire to keep his railway safe from Aura's grand design.
Ricky Mason is one of Aura's most trusted employees. He enjoys working with Aura and Walter Richards almost as much as he enjoys causing chaos.
In Grim Messengers of Doom, Aura makes sure Patriot makes a wrong turn into the scrapyards. Under his orders, Ricky Mason and Walter Richards distract and kill Patriot's crew. 'Arry and Bert then bring Patriot into the scrap shed and melt him down while Aura laughs maniacally.
If Aura ever needs an extra pair of buffers to work at the Ironworks, he will often ask for Sidney because his perpetual amnesiac condition makes it impossible to remember any of the shady behavior that occurs!
As Aura holds a grudge against The Thin Controller for getting in his way, Aura presumably also feels the same way about the Fat Controller. However, the Fat Controller and other industrial men know him personally and make dealings with him often.
In Swashbuckler, Aura attended the meeting at Last Haven, but said that he had several orders to fill, and not a lot of time, and that the meeting had better be good. He was furious that the Fat Controller had called them to "present an invitation to an invitation." He then went on to say that the Fat Controller's gathering made him sick.
Aura actively holds a grudge against The Thin Controller for getting in his way.
In 2009, a hooded Aura broke into the Thin Controller's office and stole some maps which contained the locations of disused railway lines. The Thin Controller pursued him to an abandoned gunpowder warehouse, where Aura then drew a sword and began to make advances towards the Thin Controller. When a sword mysteriously appears in front of the Thin Controller, the two begin the spar. The match is even until a small explosion occurs when they knock over a gunpowder keg, allowing Aura to escape with the Maps.
In Munitions, after Aura throws The Ministry of Defense Complex into chaos and attempts to kill General Zen, Captain Grant, Darren, Derek's driver, and several soldiers place the general on a stretcher under the orders of the Thin Controller. The Thin Controller then leads an escape from the complex. Even though Aura blows up a bridge that would make their escape easier, the Thin Controller still manages to find a way across so they can escape. Two months later, when Aura confronts Grant and prepares to kill him, Aura states that he has lost patience with The Thin Controller and his engines because of their meddling.
In Swashbuckler, the two become trapped on an upper balcony at Last Haven, surrounded by mutinous lumberjacks. In light of the perilous situation, Aura tosses an unarmed Thin Controller a flag pole, knowing his ability with comparable weaponry. Before the Thin Controller can question him, the two must fight off advancing lumberjacks. After this incident, Aura returns to the Ironworks, and commissions Walter Richards to eradicate the Thin Controller, on the basis of his long term interference with his plans.
In Aura of Menace, Aura has his men sabotage Sliggs's new engines so they would crash into Sliggs's refinery at The Mine Junction. However, after the nearby construction machines create a barricade to stop the diesels, Aura decides to take matters into his own hands. He shows up at Sliggs's indoor recreation facility and confronts him, with two of Aura's men pointing guns at Sliggs. He then says that unless Sliggs follows his orders, Aura will make him lose millions of dollars and blows up Sliggs' refinery at the Mine Junction, causing a building to crush and kill Darren and several workmen. Sliggs tells Aura that he will expose him, but Aura once again threatens Sliggs to keep quiet. He then says that there is vast quantities of oil under Ulfstead Castle, and that he knows how to get it.
In Munitions, Watson follows Aura after he finishes sabotaging The Ministry of Defense Complex and constantly barks, drawing Captain Grant's attention. Aura calls Watson a "stupid animal" and tells him to shut up. Watson then follows the Thin Controller's crew and later becomes his pet.
Along with their controller Walter Richards, Alaric and Eric are in on Aura's plan, motivated by a desire to keep their railway safe from Aura's grand design. When Aura discovers the Shepherd and the lamp are dangling from the bridge over Poll-ny-Chrink, Aura stages an accident at Kirk Machan in which the two derail in the yards, effectively preventing the other engines from rescuing the Shepherd. The plot fails however when Culdee musters up his courage to save the wanderer from the adjacent unblocked track. Following the Shepherd's rescue, the two instinctively set off to find Richards before his cover is blown as the hitman.