The appearance of The Engineer, as well as the rest of their identity, is unknown. Bunny previously remarked that they wear a long black coat with a high collar to hide their appearance, it is uncertain whether that was a joke or not. Bunny has stated that "they're not a machine", which rules out non-humanoid robots and non-sentient androids, but not cyborgs, synthetic humans or sentient androids, as Bunny does not consider any of the latter "machines". No specific gender has been stated, but both male and female pronouns have been used when referencing The Engineer, which suggests that The Engineer is genderfluid, non-binary, or belongs to a species without gender, though this has never been confirmed. No details about The Engineer's appearance have been given, not even whether they are humanoid.
The reason for the secretism around The Engineer is just as unknown as their identity. It may be due to simple anonymity, or a more serious or complex reason. It could also be because of The Engineer's status as a wanted criminal, though the name was used long before The Engineer's deeds were known to the Federation.
Criminal Activity Edit
The Engineer is a wanted criminal by the Federation, and several planetary governments. They are wanted for mass murder, genocide, and dozens of accounts of interfering with primitive cultures. The Engineer is known for introducing higher technology to primitive planets and boosting their technological progression, skyrocketing them into a space age. The Engineer also gave more advanced technology to already sufficiently advanced planets such as Earth and Jyuun (Home-world of the Xeronqyu); The Engineer designed and built Bunny's cybernetics, as well as helping in the design of her unfinished ship The USS Vainglorious. The Engineer also advanced the technology of the Xeronqyu when they were just becoming space-faring, designed vastly improved ships, creating advanced cybernetics, and The Engineer personally designed Xenon's (the Xeronqyu ambassador) cybernetics, much like The Engineer did with Bunny. Due to The Engineer's repeated introduction of advanced technology to less advanced planets, The Engineer has become an infamous criminal among the Federation.
Besides interfering with primitive species, The Engineer has also destroyed more than one planet, and a star, according to records. As such, The Engineer is charged with mass murder and genocide. The Engineer is undoubtedly a criminal, but their motives, and whether or not they can be considered "evil" or a "villain" are up for debate. Bunny, being one of very few people known to have direct contact with The Engineer, does not believe The Engineer is evil, and that there is reason behind all of their crimes, yet many people would disagree based on the severity and repeated accounts of The Engineer's crimes.
Project S.T.A.R.T (Synthetic Technological Advanced Retinal Transhumanism) Edit
Project START, from what little we know, was a project briefly worked on by The Engineer to create an enhanced version of Bunny's Cyber Eye to "further the power of the one who wields it". START was to replace Bunny's Cyber Eye, and would have a distinctively different appearance. START was to be made of a black metal, feature a black/dark grey sclera, a yellow iris, and black pupil - a considerably different appearance to the blank whiteness of the Cyber Eye. It was supposed to be commercially available to those with the money to pay for it (mainly criminal overlords and galactic bounty hunters due to the high predicted cost) through the surgical removal of their left eye, or in Bunny's case, uninstallation of her Cyber Eye. Bunny was the only person known to be offered START for free.
START was very similar to the Cyber Eye, being designed to be an improved version, it was to be able to display health, distance and name of a target, just like the Cyber Eye, as well as new functions such as the ability to track targets when not looking at them using a HUD, display the walkspeed of the target, display an optical laser to the target (only seen by the user) which would be blocked by obstructions to show if the user had a clear shot (like a red dot laser attachment for a firearm), zoom further, and fire a beam of energy which could be set to stun or to kill a target, among other features.
START was mainly combat based, and as such the project was discontinued when the Federation found out about it because Starfleet protocol would not allow such a weapon, and there was the distinct possibility of START being given to someone who would use it to harm innocents. It is unknown whether The Engineer ever actually gave up on the project or simply became more secretive with its development. Either way, the design remains intact and is possessed by The Engineer.
The project (and subsequently the plans for the device itself) was called S.T.A.R.T mainly because it was to be the first in a line of combat-oriented cybernetic enhancements, planned by The Engineer, hence it being the start of the series. It is unknown what the other devices would have been and what they may have been called.