Teacher

"I give people power, and I think there is a submissive kind of appeal to being a slave. To being numbed. Some fall for me like an alcoholic falls to drink.  Love, after a fashion.  In your case, that’s almost a defense mechanism."

- Teacher

Benjamin Terrell, known publicly as Teacher, is a villain who organized assassinations before he was imprisoned in the Birdcage. He acts as a leader of one of the cell blocks.

Personality
Benjamin is an extremely long-term planner, setting up situations that unfold years down the line. In his interactions with Saint, Tattletale speculates that not only did Teacher fake having a son, but the actions Teacher took may have served multiple plans at once, from different angles, and serving various agendas. Teacher himself claims that none of his plans ever failed.

Indeed, Teacher has supreme confidence in his own plans and abilities, often appearing smug in his interactions with others.

Teacher favors being in control, yet praises the value of submission to others, even genuinely believing his students are happier under his command. He frequently offers the use of his powers to others, and is not above lying to get his students to submit or to subsume his enemies. Nevertheless, Teacher is self-aware enough to call the time he spends under Khepri's control "karma."

Appearance
Teacher is a fat, mundane looking man, with a red face and curly or wavy brown hair with a receding hairline, balding pate and beard. While Marquis finds him to be ugly, Taylor thinks he would appear at home in a classroom, if only he wore appropriate clothing. Teacher is later seen donning a dress shirt and khakis with penny loafers. At some point, Teacher received cosmetic surgery.

He is often accompanied by his students, who dress in white outfits.

Abilities and powers
Teacher is able to give others an ability of his choice from a wide variety of Thinker and Tinker powers with a simple touch, with the disadvantage that the recipient becomes susceptible to Teacher's manipulation. In severe cases, his minions remained absolutely loyal to him as long as they had the granted powers. Teacher is able to intensify his power, making the granted ability stronger, but the power of an ability granted inversely correlates with diminished faculties in the subject, creating a dynamic where the more information a given 'student' possesses, the less able they are to express it. While Teacher has no constant connection to his students, he is able to sense both the power and the degree of influence he has over them. Teacher is able to change a student's abilities at any moment, but this becomes more difficult when an ability has had time to settle in.

In addition to his ability to grant powers, Teacher is able to modify existing ones, achieving more power at the expense of control, or vice versa. Teacher describes the process as first discovering the true nature of the power before using a sort of hypnotic state to unlock it, likening it to a second trigger.

Teacher's power decays over time. There have been almost no cases where Teacher’s power lasted more than a few days without a refresher, with the brainwashing wearing off over a few weeks or months, but in at least one case the power remained active for several years without being refreshed, with the subject showing sign similar to addiction. Despite this, Teacher claims his methods are less invasive than actual brain tampering.

Teacher's students show a form of groupthink: While individual members appear normal at first glance, they actually work within a complex system, which Taylor compares to an RTS game or computer, with every individual carrying out a specific operation, gathered in clusters with people who communicate their ideas to others in efficient ways.

It is worth noting that Teacher does not give actual Tinker powers. Rather, he pushes his ability to grant mastery of a given subject just beyond the normal limits of theory and knowledge, using several people working in tandem to achieve low-quality Tinker products.

Outside of his parahuman abilities, Teacher is a highly educated man, having used his powers to create his own tutors. Teacher is learned in history, foreign affairs, management, and internal affairs, intelligence, code-breaking, medicine and poisons, parahuman studies, accounting and trade, the sciences, the arts and strategy and tactics in military, government and business settings. In addition, he has learned from those who he called 'public speakers, flirts, con artists, actors, thieves, magicians, and cutthroats'.

Background
Benjamin Terrell started out as a cape specializing in renting out capes that could shape, limit or refine powers, or using his own power to do the same, although even early in his career, there was already suspicion of illegal activity. The number of clients dropped sharply once it became known that Teacher had a measure of influence on them, but Teacher's true face didn't show itself until he attacked a school, followed with a successful attempt to assassinate the vice president using his minions.

By 2006, Teacher had amassed himself a small army of college-aged men and women, but was also one of the most wanted capes in America. As such, Teacher moved to the United Kingdom, where he successfully plotted to kill the Prime Minister. Although Teacher claimed the assassinations were the setup for a larger plan, that plan was never set in motion. Teacher was arrested on "trumped up charges" and sentenced to the Birdcage, where he became a cell block leader.

Post-Slaughterhouse Nine
As a cell block leader, Teacher attends the meeting where Marquis introduces Panacea, where he complains about Panacea cutting into his lieutenant's business. Marquis and Panacea offer Teacher a deal in return for an explanation of the Birdcage's security.

Post-Echidna
Teacher is present when the death of Alexandria is made public knowledge. Afterward, he has a private conversation with Lung, where he offers to modify Lung's power and reveals he has contact with Saint, who is outside the Birdcage. While he rejects the offer to modify his power, Lung agrees to become a bodyguard and to keep Teacher's secrets, while Teacher continues to work on the creation of a group of parahumans under his command.

Later, during Khonsu's attack, Teacher attends a meeting organized by Cauldron. He uses his power on Moord Nag to teach her English, and bargains for his release from the Birdcage, although he is quickly rejected. His attempt to pressure Cauldron by threatening to release information about the coming end of the world is immediately shut down by Contessa.

Gold Morning
Teacher, together with some of his fellow prisoners, is released from the Birdcage during Scion's rampage. Unfortunately, Teacher, with a group of twenty to thirty other men, pretends to take control of a well-supplied alternate earth while using an unidentified device to block access to others. In fact, he is using this as a cover to take control of Dragon, although the device blocking transdimensional effects is not a fake, a fact Teacher uses to hide himself. Later, copies of the device are seen in the hands of the Yàngbǎn.

Teacher's students later take control of Khonsu, whose control Teacher gives to Cauldron, together with two of his thralls, Screen and Scanner, who assist Doctor Mother's use of the Clairvoyant. In return, Teacher receives a partnership in Cauldron, as well as protection against his enemies.

Teacher returns Dragon to Defiant, although he places extra restrictions on Dragon before doing so. During the battle against Scion in Brockton Bay, one of Teacher's minions distorts the memory of a trigger event vision so it can't fade. Although Teacher's goal in doing this is unknown, it does later help in the defeat of Scion.

Khepri pays a visit to Teacher, who is in an alternate version of Washington. She asks for a way to access the Earth where the Yàngbǎn are hiding, and Teacher gives it to her. As Khepri goes after the Yàngbǎn, Teacher warns the other heroes, including the Protectorate and Guild of her actions, at the same time, he talks to Contessa, taking control of some of Cauldron's contingency plans and asking for Contessa's aid in dealing with Khepri.A cape in wizard attire spoke up, “The Doctor is dead, I believe?”  Contessa nodded. Odd, that she couldn’t bring herself to feel badly about it. Was it because she’d spent so long trying to achieve something and she’d failed, or was it because she’d lost respect for the Doctor like she’d lost respect for herself? If she were an outside party, she was forced to admit, any outside party, she wasn’t convinced she would be able to be upset over her own death. “We need your help,” the wizard said. She nodded. “Whatever I can provide.” “First, we need information.”  “Yes.”  “Were there any other plans Cauldron had in the works?” he asked. “Nothing substantial. I can show you the tertiary plans.” “Please do. Did Cauldron have plans for if humanity failed?” “Of course.”  “We’ll need to see those as well.”  [...]  “Something this big, it has to carry on somehow. I’ll need a second in command.” “Me?” she asked. Her eye moved to the man in the horned helmet. “He’s his own man. A wild card.” “I see,” she said. More kids in white were streaming from the room. “Trickster, stop. You’re with me. We might need help navigating some of the trickier areas, if the damage to this place is extensive enough.” One boy stopped where he was, stopping beside Teacher, a dull and unfocused look in his eyes. Teacher turned his attention to Contessa, “Whatever happens in the next few hours, we need to be there to pick up the pieces. That was a factor in Cauldron’s plan, wasn’t it?” “I don’t have much of a role,” Contessa said. “I can’t do anything when Scion’s on the table.” “To the contrary,” Teacher said. “We very much need your help, or we might.” She narrowed her eyes. “With?” “Saving us from ourselves,” he said. “Case in point, we’ve got a crisis that involves one little lady I think you’re familiar with.” He held up his phone. A picture was displayed. It took her a moment to recognize the person in the picture, and not because it was an unfamiliar face. “Weaver?” she asked. - Excerpt from Interlude 29 He is seen during the final battle, giving the ability to speak to Doormaker. After the defeat of Scion, Teacher offers the same use of his power to the drained Khepri, but she violently refuses.

Post-Gold Morning
Following the death of Scion Teacher sets up multiple villains, helping them to become powerful by providing instructions to be followed. Imp speculates that Teacher does this to spread his chances, to be connected to someone in power if at least one of the villains succeeds.

Teacher himself is seen together with Satyr, rescuing Ingenue from the Wardens before meeting with Contessa. Next, Teacher meets with Marquis as he tries to recruit Panacea. Teacher claims his plan is to create a team bigger than any other, with powers bigger than any they have seen so far; by bringing the Shards back together into their greater whole, allowing a joining or sharing of different powers.

Meanwhile, the Undersiders plan to take down Teacher.

Early-Ward
Had been knocked down by the Undersiders but was still around.

He had expanded upon his previous business, including recruiting tinkers and recovering Cauldron vials.

He was the main perpetrator of the Gimel Portal Attack, using the war with Earth Cheit as a distraction and with plans to recruit or take down Goddess.

Post-Fallen fall
Had a hand in stirring up Cheit forces.

Made moves against Goddess.

Tried to take over the prison, by sending food that made people immune to the master power of Goddess, as well as Lung, Blindside, Kingdom Come, and the Pharmacist, but ultimately failed.

Post-Time Bubble Pop
Unbeknownst to the heroes of Earth Gimel, Teacher had methodically been laying a large scale trap for them in the form of pieces of correspondence or diaries or the like that were designed to undermine them, and their relationships with their teams. At the same time, his alliance with Earth Cheit led to his ever-increasing control over that dimension.

He had plans to similarly subdue The City and Earth Shin, but was forced into a short war with The Wardens, that besieged the Cauldron Compound. Teacher was able to manage the situation until Breakthrough and The Heartbroken broke out Contessa, who was able to turn the tables on Teacher. Once the surviving heroes reached his command post, he revealed some of his goals and insights into shards but was able to evade the arrest.

Days later he was seen on Earth Cheit with some of his lieutenants.

Post-Attack on Teacher
Teacher was found by Breakthrough in the shard-realm, partially melded with his agent. He was puppeteering other agents through tinker-tech deployed there. Antares destroyed his setup, which led to him losing any control over his thralls. They promptly took him hostage.

Teacher was recovered from Earth Cheit by Contessa and the Wardens.

Teacher was being escorted by Contessa to the Wardens HQ when a cataclysmic event occurred. He temporarily escaped after Contessa was transformed into a titan but was recovered by the Wardens' strike team and taken into custody.

The Ice Breaks
Teacher cooperated with The Wardens. Namely by providing information and access to other Earths and hard to reach parahumans.

Trivia

 * Teacher is likely the leader of cell block T, as that is the cell block housing his lieutenant.