The Slave Pens is located deep underwater in the Zangarmarsh.
Ner'zhul caused the collapse of Draenor World, creating a complex network of caverns beneath Coilfang Reservoir.
After Vashj's Naga forces occupied the area, they enslaved a large number of Broken and built a complex network of pipes and valves, transforming it into an underwater military fortress.
The Black Temple's needs for food, medicine, weapons, equipment, and war machines are mostly produced by the Coilfang Reservoir.
It can be said that the Coilfang Reservoir is the logistics base of the Black Temple.
The Slave Pens enslaved over 30,000 Broken, prompting the Broken leader Akama to protest to Illidan on numerous occasions.
However, for some reason, Illidan did not grant these Broken their freedom.
Vashj captured Horde leaders, including Thrall. Of her three thousand elite guards, fewer than five hundred were killed; the rest laid down their weapons and surrendered to Vashj.
It wasn't that the Orcs weren't brave enough in battle; it was just that most of the Personal Guard were noble sons of the Orcs who joined this force closest to Thrall through connections.
The noble children are not like the brainless, single-minded, and impulsive poor Orcs; none of them are willing to risk their lives for Thrall.
Having captured Thrall, Vashj was in a dilemma, knowing that Guardian Medivh Horde.
While the Star Mage Medivh might not be able to conquer Coilfang Reservoir alone, if he were to come to rescue people, it would be virtually impossible to defend against.
Kael'thas came up with a good idea.
"Why not scatter the Orcs among the Broken, and not treat Thrall any differently, but let him become a slave like any other soldier?"
Vashj hesitated, "What if Thrall contacts the soldiers and they respond with overwhelming support?"
Kael'thas confidently replied, "You can rest assured. Thrall has always been high above, a god-like figure among the Orcs. If he loses his Savior aura, he won't be recognized by the other Orcs. You can announce publicly that only Thrall will receive preferential treatment, tempting the Orcs to impersonate Thrall."
Vashj recalled the farce of the real and fake Thrall at the banquet and thought this was a good idea.
Of the more than two thousand Orcs, if even one-tenth were willing to impersonate Thrall, how could Medivh possibly distinguish the real Thrall even if he secretly searched for him?
Vashj's beautiful eyes shone brightly. "Excellent idea! If even we don't know which one is the real Thrall, it would be strange if Medivh could find Thrall."
It's important to know that the Slave Pens was located deep within the Coilfang Reservoir, with only one exit, and was heavily guarded. Over the years, not a single slave had escaped.
After arranging for Thrall's arrival, Vashj sent the captured Cenarion Circle Druids to the Underbog.
The Underbog is home to natural life. It existed before the Naga invasion and is inhabited by a large number of spore life forms, serving as the main food source for the Black Temple.
Marsh Lord Swamplord Musel'ek is a Draenei Broken, a seasoned hunter, apothecary, and his specialty is turning Druids into hunters' pets.
He developed a special potion that, when given to Druids, prevented them from transforming back into human form from their beast form.
Swamplord Musel'ek assured Vashj, "After taking my medicine, the Druids will forget their original identities over time."
Vashj trusted him completely, entrusting him with Druids such as Ysiel Windsinger, Hamuul Runetotem, and Guardian Remulos, turning them into the hunter's pets.
Other Horde leaders were not spared either; Vashj treated them all the same, turning them into slaves.
The Blood Elves of the Horde are the fewest in number, making them particularly conspicuous in the Slave Pens.
Thanks to Countess Liadrin's sweet words to Vashj, the work assigned by the Blood Elves wasn't too difficult; their daily task was sewing armor.
Other Blood Elves could tolerate it, but Regent Lor'themar was the most unwilling, especially after he grew old and his emotions became very unstable.
That morning, Lor'themar finished sewing a set of armor, but felt aches and pains in her back and was about to close her eyes and rest for a while.
Suddenly, a dark figure appeared and quietly hid in his shadow.
The shadowy figure showed him a wisp of magical power, as vast as the starry sky.
Lor'themar was secretly delighted; only the Guardian Medivh possessed such power.
"So you're that incompetent piece of trash, Lor'themar?" Medivh mocked mercilessly.
"It's me, Great Guardian, get me out of here," Lor'themar pleaded in a low voice.
"Tell me first, where is Thrall?" Medivh said awkwardly, "The Orcs are all working in the mines. There are at least five hundred Orcs there claiming to Thrall."
Lor'themar said with a mournful face, "I don't know. I couldn't tell either after Thrall took off his armor."
"You're a complete waste. If you can't find Thrall, you'll be a slave here forever." Medivh cursed angrily before disappearing.
Lor'themar was heartbroken; her hopes of gaining freedom had been dashed, and she had no choice but to pick up her needle and thread again.
Kael'thas's plan was brilliant, and even the Guardian Medivh was powerless against it. After several unsuccessful attempts, he could only leave unwillingly.
Thrall mingled with the Orcs soldiers, toiling away every day under the command of the Naga, sometimes working more than ten hours a day.
As Lor'themar said, without the insignia of the Orgrimmar breastplate, even the Orcs wouldn't recognize him as Horde, the Warchief Thrall the great Savior.
After some time, seeing that no one came to his rescue, Thrall realized that he could not rely on anyone and had to rely on himself.
Thrall came from Servant background in Karazhan, was able to endure the arduous daily labor.
The Orcs nobles gradually couldn't bear it anymore, and complaints arose everywhere. Some even secretly cursed Thrall as a useless piece of trash who had dragged them down with him.
Complaints spread quickly, Orcs became lazy, refusing to work no matter how much the Naga overseers whipped them.
It's well known that Orcs are notoriously lazy, and Lordaeron suffered greatly because of this in the past, sowing the seeds of the kingdom's downfall.
The Orcs' laziness also affected the industrious Broken, whose leader Mennu the Betrayer, was so worried about it that he tried many methods, but none of them worked.
Thrall knew his chance had come, and he secretly went to see the Mennu the Betrayer.
"Who are you?" asked the Mennu the Betrayer.
To cut corners and reduce their workload, many Orcs called themselves Thrall. Thrall, however, did the opposite, bowing and scraping as he said:
"My lord, my name is Gudan."
"Gudan, do you have a way to solve the Orcs' laziness?" Mennu asked, his brow furrowed. "They say it's because their Fel isn't being replenished."
"My lord, those are all excuses," Thrall said viciously. "I understand the nature of Orcs; I have ways to make them even more industrious than Tauren."
Tell me about it.
Thrall wore a gloating expression. "Just give the rule that anyone who doesn't reach 60% of the workload of the top Orcs will be executed."
Mennu asked skeptically, "What if the Orcs unite and no one is willing to do more?"
Thrall chuckled and said, "Orcs are masters of infighting and love watching their people die; they're willing to work themselves to the bone for it."
Mennu decided to give it a try.
Thrall's method worked wonders; the Orcs worked like madmen, and their productivity increased several times over.
"If we had known about this method earlier, the Lordaeron Empire would not have fallen," Mennu said with emotion.
Thrall was rewarded for this and was honorably appointed as a foreman, overseeing the twelve Naga.
The overseers were treated much better than the slaves; they had snow-white clam meat with every meal.