In any case, this is a list of bosses in a videogame the author had been scripting, but considering it's age, likely incomplete.
Bunkerbuster: A heavy assault, antiarmor, and anti emplacement unit. Early model, fed enough weapons that it’s grown beyond the original size and firepower specifications, at the cost of gaining enough independence to be a potential hazard if allowed to develop further. The project was shelved due to lack of subtlety, precision, or low cost per unit compared to the newly developed Wraith units, and the only working prototype was kept at the main storage facility as a guard dog/building specific mascot that rarely saw combat, but was usefully intimidating, and could reliably destroy anything else that would stored in the warehouse if it escaped. Vant crossed paths with it fairly early in his rampage, and the guards only started getting really serious after he destroyed it in three minutes and consumed the remains. It was four legged, had six rocket launchers, two to each arm, one each for the shoulders, and it’s claws had the dual purpose of allowing it to brace itself and dig through almost all materials. It a heavy cutting laser was intended for later designs, but never implemented.
The Lords of Silence: The Twelve Lords of Silence, four of which are reserved for the Queen of Dead Echoes’ honor guard. They are all weaker, weaponless, nonsentient imitations of her. Fought twice, once when the eight deployed as a defense against airstrikes drive Vant back indoors, where they don’t have enough room to maneuver, and the second time shortly after Vant absorbs Bombshell, where he’s actually able to hit them. They get called back shortly after he starts killing them, but he still gets at least three. He is, however, incompatible with their masks and robes, as they’re designed to show absolutely no identity, and conceptually opposed to his nature as a face stealer variant.
Rook: The leader of the elite squad of security androids native to the facility. Essentially a flying, better armored, ridiculously fast Shock Trooper, it uses rockets placed strategically around it’s body to outpace most targeting systems, including Vant’s, and has an inherent immunity to homing effects. Four working copies have been made, and trained in assistive movement, but mass production was being held off until a solution to the pausing glitch as they connect could be found. They all ambushed Vant soon after the Lords of Silence drove him back inside, but he was able to exploit the glitch to defeat and consume them.
Yuuyel: A Machine King commando sent to investigate the facility for completely unrelated reasons who ends up crossing paths with Vant. Vant presumes he’s another guard, and Yuuyel decides that the rampaging robotic abomination is probably something he’s allowed to shoot. He’s also believed to be working with Vant from approximately the minute he makes himself known, and the “shoot first, questions later” attitude of the base security gets several of them court martialed for criminal negligence after the actual situation comes to light. Protagonist of Yuuyel Mode, which follows his misadventures as he attempts to use his Covert Entry Warrant and stealth specialization to discreetly sweep the Sulieman Research Facility for highly illegal weapons, only to be mistaken for an infiltrator working with the Rogue (Vant), and shot at. Uses a rocket launcher with an underslung plasma cutter, and has a grappling hook launcher attached to each limb. The trick to defeating him is to attack his grappling lines with heat or cold, and use explosives when he tries to hide. Electrocuting them also works, but only if he’s not grounded at the time.
Bombshell: A research subject, Bombshell was believed to be a conglomeration of severely damaged Bluefire Drone, several Type III Combat Doppelgangers with the basic machinegun loadout, and a recently shot down jet fighter. The working theory was that the Type II Artificial Wraith had attempted to repair itself with nearby materials and accidentally absorbed the not quite metal of a mostly dead Combat Doppelganger looking for new parts to copy. It is believed to have either then shot down or merely recovered a previously crashed fighter/bomber, and proceeded to absorb it. It is known to be mostly still loyal to the U.S. military, and capable of flight, transformation between several preset modes, and generating complex ammunition types, all facilitated by Bluefire. It can also apparently make generated projectiles explode into Bluefire on contact, suggesting more innovation than normally expected of a drone, and was also being vetted for tampering before copies were rushed to mass production.
Tanner Hobson: An optional, hidden boss, she made a segmented whip/club/chain out of pistols, with hinges attached to the bottom of the barrel and the back of the slide. The triggers were also removed, although the trigger guard was kept for the handle. While it was theoretically possible to reload manually, she kept it loaded with magic, and designed the hinges such that they couldn’t end up pointing any of the barrels at herself with any ease. She made it with facility supplies, deducted from her own paycheck, as something of a hobby, and used the working prototype to attack Vant at least partially because she wanted to see how well it worked. Put up a reasonable fight, and ran after being disarmed. Vant was unable or unwilling to follow.
The Queen of Dead Echoes: An attempt to copy the Dead Messengers, with several misconceptions about their actual creation process. As a result, she’s powerful but quite flawed, and her weapon, Piercing Echo, was created for her and bonded to her at birth, unlike a true Dark Nature. Her actual inherent powers allow her to replicate or cancel sounds that occurred in the local area, including shockwaves, and travel at the same speed. This allows her to match velocities with supersonic projectiles, one major distinction from the Lords of Silence, and she can also produce noise rather than simply modulating silence, however they do share in common the inability to move slower than the speed of sound. Her movement abilities are shared with her weapon, which takes the form of a five pointed star that splits into psuedo boomerangs. Freeing her is Vant’s objective, although she is quite possibly the final boss.