Bosses are found on Assassination missions. Each boss has a set of lines to "taunt" the Tenno sent to kill them. They often drop mods and resources upon death. Depending on which Boss the player is fighting, Blueprints of Warframes parts and special Weapons parts will often be rewarded upon mission completion.
On the other hand Assassins hunt players in random locations. Their appearance are triggered by various actions done by the player, such as killing a Boss or assisting an opposing Factions in Invasion missions.
All bosses and assassins have a chance to drop an Orokin Cell upon death.
Captain Vor Is one of the few figures in the game that understand ancient Orokin technology and go as far as utilizing it and embracing it with his own technology in the form of his Seer pistol in which he drops parts for when killed, or his armor which is powered by a Void Key that he can use as a ranged attack beam weapon. He first appears on Mercury, and thus is the first boss that players must fight, he then appears fully alive on Phobos as a dual boss battle alongside Lieutenant Lech Kril, and then later still as a Corrupted version in the Void.
- Main article: Councilor Vay Hek
Councilor Vay Hek is the hidden boss located on a secret base on Earth. He is the most political Grineer figure players meet, marked by the Lotus for extermination for upsetting the balance in the system by killing several political opponents. Paranoid for being targeted, Vay Hek now hides in a secret location in which players must extract Beacons found from Prosecutors on Ceres Grineer Shipyard in order to find him. Vay Hek is also heavily modified with Grineer alterations, with little flesh left noticeable while he rides in his giant Terra Frame machine.
- Main article: General Sargas Ruk
General Sargas Ruk is the final boss of the Saturn system. The head of one of the Grineer Artifact extraction projects, Sargas Ruk was targeting by the Lotus for annexing Tenno-controlled dig sites. Ruk enjoys Grineer augmentation, even going as far as replacing the lower part of his arm with a flamethrower and replacing his normal vision with a single augmentation in the center of his helmet.
- Main article: Kela De Thaym
Kela De Thaym is the boss of Sedna. According to the Lotus, all female Grineer undergo combat training. However, in Kela's case, she was the most battle hungry and extended her own term another decade before returning to the Grineer council. She has influence within the council, which is the main reason why the Lotus has targeted her for assassination as her death would cause a power vacuum in the system. The only female Grineer boss players encounter, she was specifically built for combat personally by the Sisters, with most of her body replaced with augmentations.
- Main article: Lieutenant Lech Kril
Lieutenant Lech Kril is the final boss of Ceres, and makes an appearance on Phobos alongside Captain Vor as a dual boss battle on the planet. A revered war hero to the Grineer, Lotus has targeting Kril so that his death could create possible instability within the Grineer and intimidate them, although she also fears he may become a martyr with Grineer riled up to avenge his death as a result. His rank as a "war hero" is rather strange considering his apparent low rank in the Grineer military, although his near impenetrable body suit and massive temper may prove that he indeed as ruthless as Grineer say he is.
- Main article: Tyl Regor
Tyl Regor is the final boss of the Uranus system and the head researcher focusing on Grineer gene repair in an attempt to reverse the negative effects from excessive cloning. He was targeted by the Lotus in order to slow down this progress, ensuring that the Grineer do not become more powerful. He apparently has an interest in fashion somewhat, as some of his remarks in the mission hint at, such as mocking the player's warframe by comparing it to a halloween costume.
- Main article: Alad V
Alad V was the head of Grineer Relations and reported directly to the Board of Directors. In spite of his position, Alad V showed a particular contempt towards the Grineer (whom he refers to as 'dogs') and to a lesser extent, the Tenno. He is the most decorated Corpus boss in terms of his involvements with many Events. He eventually became obsessed with the the promise of biological research on the Infested, with the hopes of creating very powerful bio-weaponry, going as far as using Technocyte on his own armor and sacrificing prototypes from his Zanuka Project.
- Main article: Ambulas
Ambulas is the boss of the Pluto system, representing a black MOA but with more dangerous attributes. Besides having high health, alloy armor, and a proto shield, it has a high damage machine gun and two abilities that mirror Fire Blast and Pull, making it a dangerous opponent when also surrounded by other Corpus units. It was targeted for assassination by the Lotus to prevent further Ambulas models to be manufactured, although it is unknown if more models exist.
- Main article: Hyena Pack
The Hyena Pack are the final bosses of the Neptune system, made up by 4 unique and deadly variants of the Hyena proxy. They work in packs of up to four with each of them possessing a unique set of abilities. Each Hyena possesses a plasma repeater and are far more agile than any other enemy in the game, including Zanuka and Zanuka Hunter. Alongside their agility, they can also jump on to and cling to walls, though they cannot wallrun. Lotus has marked them for assassination for obvious reasons, as they are a very dangerous proxy group and destroying the models may slow down further production.
- Main article: Jackal
Jackal is the final boss of the Venus system, and represents the first Corpus boss that players encounter. Although a more bulky and old model compared to more recent Corpus robotics, the Jackal possesses invulnerable shields, a giant shockwave ability to knock players down, and one of the most powerful corpus weapons, the Plasma Grenade Cluster. Dissected models of the Jackal can be found in some Grineer tilesets, either showing that the Grineer have interest in utilizing Corpus technology, or that they are simply purchased merchandise.
- Main article: Raptor
The Raptor is a Corpus Boss found in the Europa system, and the only flying Corpus boss in the game. It has very high stats and heavy hitting weapons, including launching high damage missiles that seek players, deploying mines and firing explosive laser bolts, making fighting in the open a difficult task. It was marked for assassination for being a high threat risk, as more models of this proxy could result in dangerous repercussions.
- Main article: Sgt. Nef Anyo
Sgt. Nef Anyo is the final boss of Mars system, in charge of the Corpus solar rail systems, and has been using them to obtain Cryopods with dormant Warframes for resale to rogue scientists and splinter groups. When confronted by the player during the mission, he has a very aggressive tone towards the Tenno and warns the player that they are making a fatal mistake by attempting his assassination. He also may demand information regarding Orokin secrets, or like Tyl Regor, make fun of the player's Warframe or teammates.
- Main article: Phorid
Phorid is an infested boss, found when an infested invasion manages to "Infest" the boss node. After defeating it and finishing the mission, you receive Nyx Helmet, Chassis, or Systems Blueprint. Upon death, Phorid has a chance of dropping rare Resources of the planet he has appeared.
- Main article: Lephantis
Lephantis (previously known as J-2000 Golem) is a massive Infested boss introduced in Update 10. It was originally going to replace the now retired J3-Golem boss but was moved to the Orokin Derelict tileset instead. Lephantis requires players to craft a special Derelict Assassination key, which requires five Golem Nav Coordinates; items only obtainable though Derelict missions; missions which require regular Nav Coordinates found in normal missions.
Assassins are boss-like NPC's that hunt players in random locations after doing certain things against their Factions, earning their respective Death Marks in the process. In the Stalker's case, he will target players who have defeated one of the regular enemy bosses in the game as "revenge". The Zanuka Hunter and The Grustrag Three will target the player when they aid the opposing faction in an Invasion mission. They usually drop rare resources and exclusive weapons when defeated.
- Main article: The Grustrag Three
- Main article: Zanuka Hunter
Zanuka Hunter, also known as Harvester is a gray-colored Zanuka proxy controlled by Alad V. During missions, it will attack one targeted Tenno until either the Tenno or the Zanuka Hunter dies. It appears rarely, in a manner similar to the Stalker.
- Main article: Stalker