The Operator represents the most pivotal figure in the Tenno's journey to bring balance to the Origin System, yet they are not encountered until long after the Tenno awaken. Many new Tenno are still unaware of the Operator's identity or existence, and are understandably astonished when they attain revelation.
During the Second Dream, the true identity of the Tenno is revealed to be one of a group of children – pre-teens or teenagers – survivors of the Zariman 10-0 colony ship, piloting the warframes remotely through a phenomenon called Transference. The Lotus calls these children "Operator". The player, the central Tenno, is represented by an Operator who they can customise to their satisfaction. The player, as the Operator, will often comment on situations the Tenno encounters during their missions.
When starting a mission, the Operator will often comment, either with a generic statement or with one more specific to the faction being faced. If a mission starts in Archwing or Submersible mode, the Operator will have different lines (these do not trigger if the mission transitions into Archwing or Submersible partway through).
"We know the mission; we will not fail."
"My warframe is the hand, and I am the will."
"The Lotus is counting on us."
"We will bring honour to the Tenno."
"Transference signal strong; we're ready for battle."
"Alright, let's get to work."
"I hope we're ready for this."
Against the Grineer
"Ballistics and archaic weapons – crude and dangerous, just like the Grineer."
"The Grineer used to be builders; now all they make is war."
"You'd think they'd clone something a little less… ugly."
"The Grineer deteriorate over time… is that what makes them violent?"
"The Grineer have no honour."
"The Grineer prey on the weak, but we prey on the Grineer."
"If we could avoid alerting them, this may be easier."
Against the Corpus
"So… the Corpus are just a cult, worshiping money."
"These Corpus remind me of the Orokin – selfish, greedy."
"They'll have plenty of robotics. Corpus never fight for themselves."
"Corpus technology won't be enough to stop us."
"Okay, ready to blast these machines into spare parts?"
"We'll put an end to this Corpus greed."
"Corpus have tech weapons, we'll need to be careful."
"Watch for security systems."
Against the Infested
"I remember these monsters from long ago."
"Disgusting monstrosities. I think they absorb their victims."
"Infestation, an Orokin weapon… that backfired."
"We need to purge this place, as we did in the old days."
"Some explode when killed. We will need to strike and move."
"Ancients are powerful, age and feeding has made them strong."
"Be on guard for the Ancients."
"We're immune to the Infestation but they still try to kill us."
"What a mess. Let's clean this up."
"Alright, biological attacks, be ready."
"Alright, flight system looks good."
"Oh… this looks fun."
"Archwing submersible deployed!"
"We need to watch for aquatic targets."
"I wonder what's down here."
After killing many enemies in quick succession and then experiencing a lull in combat, the Operator will often reflect on what just happened.
"My warframe is strong."
"Attack us, and we will counter."
"I will consider what I have learned from this skirmish."
"That was a close one."
"Transference still holding."
"We fought with honour."
"Move and strike, we have to win this."
"For the Lotus!"
"For the Tenno!"
"Let's go on the offensive!"
Exploring the map
"Wonder where this goes."
"Need to keep a lookout for supplies."
"How big is this place?"
"Mod over here!"
Upon taking significant damage in the warframe
"The Transference makes this hurt!"
"Internals damaged, we need to watch it."
"We've been damaged, need to heal."
"Need to find a health orb."
Upon being revived
"Right, we're on our feet."
"Transference resynced; watch it."
"Back on your feet, warframe!"
"That was close!"
When running Assassination missions, taunt transmissions from the boss will often be followed by a retort from the Operator.
"Fear will not control me."
"Huh… you're barely making sense."
"Keep talking… we're still trying to figure out how dumb you are."
"Time to shut you up for good."
"You are the mission. I will not falter."
"Say what you want, we're still coming for you."
The Tenno Operator has lines in the quests The Second Dream, The War Within, Apostasy Prologue, The Sacrifice, and The New War, while also directly playing major roles in Chains of Harrow and Chimera Prologue. The Quills representatives Onkko and Little Duck, as well as the Necraloid Syndicate, will only interact with Tenno Operators.
During The New War, a paradoxical form of the Operator was revealed, known as the Drifter. The Drifter represents a version of the Operator that was never rescued from the Zariman. After The New War, the player can switch between Operator and Drifter forms as desired, with the Drifter being functionally identical to the Operator in gameplay.