Teach

Teach, also known as Oleg or All-Slayer Oleg, is a Hero in Xenoblade Chronicles 3. He is the commander of Colony Gamma. Teach also goes by the name, Inscrutable Teach.

Appearance and personality
Teach has blondish-white hair, blue skin and pointed ears similar to an Indoline, and a blue diamond on his left cheek. Teach wears a purple Japanese themed coat with a white Japanese undershirt underneath, white armored armbands, black pants and sandals.

Going Beyond Power
Teach is first encountered during the Hero Quest Going Beyond Power. Walking up to them through a guard of honor made by the Gamma soldiers, he warmly welcomes Mio, Taion, Sena back in Colony Gamma, saluting them with a smile. He doesn't show hostility to the Kevesi members of the party, offering all of them to take the time to rest. But as he turns their back to them and walks away, his smile disappears, replaced by a serious expression.

The party takes the time to catch up with their old friends in Colony Gamma, before deciding to talk to Teach and explain him everything about Ouroboros and what happened since the mission at Alfeto Valley. Sensing the serious nature of their talk, Teach offers them to relocate to a more convenient location than the Commander's Office. They agree to meet up at the training grounds later to head there together, and the party leaves. Seemingly alone in the Commander's Office, Teach laments the fate of some of the best soldiers he has known, now traitors to Agnus. Glancing at Consul G hidden in the shadows, Teach promises to deal with them to protect the world.

Teach and the party leave the Colony to head for the Commander's "good place". On their way, Teach shows them how to climb up slippery sand slopes, and the party inherites the Traversal skill Scree Walking. They eventually reach their objective, the Transcendent Retreat. There, Mio tries to talk to Teach, but he interrupts her, revealing that he has known about Ouroboros from the beginning, and that he has lead the party to this place to eliminate them away from their old friends's eyes out of respect. He summons his Blade, forcing the party to fight him.

Mio tries to reach him and make him understand they aren't enemies of the world, and they only want to use a power they obtained by pure chance to make the world a better place and protect the lives in it. Eventually, Teach chooses to believe in them and to spare their lives. Disappointed, Consul G appears and transforms into Moebius to take care of Ouroboros himself. With Teach's support, the party defeats him, and heads back to the Colony, where Mio and Noah destroy the Flame Clock.

Teach reveals to the party he had to test them to make sure they weren't losing themselves in their newfound power, because himself knew someone who had. Mio asks him to join them on their travels, to see for himself what they are doing with the power of Ouroboros. Teach accepts, and becomes available as a Hero.

Teach's Teachers
To help Colony Gamma survive, Teach asks the party to train the young soldiers.

Shadow of Enmity
After this is done, Teach starts a large-scale maneuver exercise on Everblight Plain, where he has the soldiers of Colony Gamma attempt to claim three supply drops, while the party tries to stop them. He tells the soldiers that they must never hold back, and in doing so will do their enemies an honor. However, Kyrie goes missing during the exercises, and a mysterious man contacts Teach, telling him Kyrie is his hostage and telling Teach to come meet him. While reluctant to burden others with his past, Teach accepts the party's help in order to rescue Kyrie. He explains that in the past, a battle involving Colony Chi at the nearby Rottswoe Battlescar had lead to both sides being wiped out. There, he is confronted by a man who knew Teach in his past, as "All-Slayer Oleg," the ruthless leader of Colony Chi. The man was the sole survivor from the Kevesi Colony in that fateful battle. While Teach tells the man that they do not need to fight, he insists on having his fight with Teach. Teach initially holds back while battling against the Avenger of the Colony, seeing no reason for them to fight. However, Kyrie reminds him of his words from earlier, and Teach decides to fight with every ounce of his strength, as to honor the enemy soldier. At this point, a new art for Teach is unlocked, All-Slayer. After the fight ends, Teach swears to remember the soldier's last words. When Taion asks him about his past, he explains that he cannot tell them due to an oath he made. After the battle in which Colony Chi and its opponent were destroyed, Teach swore an oath with Consul G. "To impart wisdom to those who succeed them. To teach them strength, and the tenets of battle. That this humble wish should spark, we swore never to divulge the secrets of the past." With that oath, he took on a new role as an educator. Accepting his past as a burden he must bear, he does not speak about it, feeling that doing so would only be a collection of empty excuses. However, he also does not forbid the party from trying to learn about their past, stating that if they wish to do so, it is a matter for them and them alone. He then congratulates the squadrons for an excellent performance in the training exercise.

Other Appearances
Teach can be among the recruited Heroes to aid the party in the final battle against Z, declaring his intent to stamp out the evil at its source as he is summoned. After Z's defeat, Teach can be seen on the Agnian side as Aionios splits back into the two worlds it was created from.

Lore
Teach is initially introduced as the wise commander of Colony Gamma, where Sena, Mio, and Taion were stationed prior to becoming Ouroboros. His ascension quest reveals some of his past as All-Slayer Oleg, the Commander of Colony Chi. A party chat afterwards about All-Slayer Oleg reveals that Colony Chi was a prominent power in the Agnian military, and was merciless and vicious. However, the Colony never reached Gold rank, despite their startling results. They were sacrificing their own troops in order to win, with no mercy for their enemies or allies, prioritizing might above all. While this resulted in their ranks being made up of powerful veterans, it was unsustainable and they eventually met their end in the battle at Everblight Plain, where they were mutually annihilated along with several opposing Kevesi Colonies. According to the records, Oleg was also slain in that battle, though he survived and became the commander of Colony Gamma, having sworn to be an educator. Taion theorizes that Teach instilling caution toward "power" in them had been due to wanting to warn them against making the same mistakes he had as Oleg.

As a boss

 * Inscrutable Teach (boss)

As an NPC
Teach can be found at Colony Gamma when not engaged as the party's Hero.