The Lord of the Rings: Lords of Middle-earth.

“If I remember correctly, it was the dwarves mining mithril that disturbed the Balrog lurking underground! This Balrog killed Turin VI and then killed his son, Nain I, the following year. It must be him…” Roland shook his head and said regretfully.

"Something's strange. Why is the dwarf king holding out here?" Roland asked, glancing at the unyielding statue of Nern.

“Bahrain? Stop crying! We need to figure out what’s going on! Tell me! Where does this hall lead?” Roland went over and helped the sobbing Bahrain up.

"The third hall, also called Massabul Hall! After Massabul Hall is the bridge! In the words of outsiders, it is called the Turin Bridge!" Balin said to Roland and the others as if it were a matter of course.

"And what else? How did the dwarves escape from here back then?" Roland immediately pressed for an answer.

“Your Highness, what do you mean…” Omske and Kaslow exchanged a glance and both had their own guesses.

“Some people crossed the bridge and left through the east gate, while others went up the endless steps and climbed to the top of the mountain…” Balin recalled the history of the dwarves.

"Slap!" Roland slapped him hard.

“Yes! It’s the Endless Stairs. Where is it?” Roland became increasingly certain of his guess.

“Before the bridge, after the Massabur Hall!” Bahrain said.

"It seems that King Nien I died in battle to buy time for the people to escape while trying to stop the Balrog!" Roland confirmed his guess.

“Look, the traces of stone crystals here extend up from the cliff! And right below this cliff is a large mine! The Balrog climbed up from below! If I’m not mistaken, the location of Massabur Hall shouldn’t be connected to the cliff, so the Balrog can’t enter directly from the cliff. Therefore, it can only attack this fourth hall, which is closest to the dwarves’ retreat route!” Roland analyzed.

“That’s right! The Massabur Hall is not connected to the Great Mine; only the Fourth Hall and the Second Hall are connected to it!” Bahrain immediately admitted.

“The dwarves want to retreat, and Massabur Hall is key! But Turin VI and Nern I are clearly not going to sit idly by; they must have fought the Balrog here for many rounds! You can tell from the scattered crystal paths! The Balrog has come up and down this place several times!” Roland pointed to the radiating crystal veins extending into the mine. “That’s right… that must be it…” Balin’s eyes welled up with tears.

Roland could already picture that scene...

The once-thriving mithril reserves of Kael'thas-d'Or were gradually depleting, forcing the dwarves to venture deeper into the earth in search of it! Perhaps it was some unfortunate soul who stirred up the Balrog, awakening it... and tragedy ensued! The already declining dwarves lacked high-level combat power. Initially, the Dwarven King led his soldiers in several counterattacks, but this awakened Balrog was no ordinary Balrog; it was the Scourge known as the "Fire of Udon"! He was once one of Morgoth's most trusted subordinates! One of the few who survived the War of Wrath!
Under the relentless onslaught of the Balrog, the dwarves were overwhelmed and unable to maintain the operation of Moria. This marked the turning point that led them to abandon Moria! The death of Torin VI cast a shadow over the hearts of all the dwarves. Grief-stricken, the dwarves, led by King Ner'n I, began to defend the Fourth Hall and rallied their people to evacuate. Groups of dwarven women and children crossed the Anduin River through the East Gate to the Iron Hills and other places, while others ascended the Endless Stairs to the summit of Silasigir and migrated westward to the Blue Mountains and other western territories…

The migration of the entire group was a massive undertaking, not something that could be accomplished overnight. King Nirn led his elite dwarven guards to garrison the area. Clad in heavy armor strong enough to withstand dragonfire, and wielding mithril shields and heavy axes, they fought the Balrog time and again! Unlike the Balrog, who could each descend into the abyss to heal his wounds and regain his strength with lava, the number of elite dwarves dwindled...

An unknown amount of time passed… perhaps a day or two, or even a month or two. Almost half of Moria had been emptied, and countless dwarves were stranded in foreign lands. They came to the Lonely Mountain and built a new home—Irubor! Meanwhile, Nien remained steadfast in his mission as king! He held firm in the Fourth Hall, firmly blocking the Balrog outside the Halls of Malzahar…

Once again, the Balrog attacked. This time, there were no civilians left in Kael'thas-d'Urb. The few remaining elite dwarves gathered in the ruins of the Fourth Hall, where King Ninn was also present! They watched the fiery red figure outside the plaza, feeling the intense heat emanating from it! The Balrog lashed out with its fiery whip, lashing the void, melting stone into crystal wherever it passed! The dwarves stood firm in their ranks, awaiting the final moment!

Facing the Balrog, the elite dwarves seemed to have returned to the battlefield of the War of Wrath, and for the first time, they felt fear! They dreaded this unkillable monster, one that even the Overlord could not contend with. The last of the elite dwarves huddled together, their eyes flashing with anger and fear... but they did not retreat!
"Kill!" Nien roared, brandishing his battle axe. The king of Caesar'dum would not abandon his territory, just as Turin would not abandon its people. When all the people left Caesar'dum, this dwarven army would face only victory or death!

The two sides clashed once more! The colossal Balrog, like a thousand horses, crashed into the dwarven ranks. Its scorching flames whipped up an unfortunate dwarven soldier, this third-tier berserker, who didn't even have time to retaliate before being burned in two at the waist! The aroma of roasting meat wafted out, but no one found it pleasant; only nausea and rage filled the air! Armor strong enough to withstand dragonfire was easily torn apart by the Balrog like paper… At this moment, the dwarves realized that this was no ordinary Balrog! This was one of the witnesses and survivors of the War of Wrath—"Udon's Fire!"

"Fight! For our homeland!" Nien's teeth were already bleeding from clenching, but he still fought hard against the Balrog. His king's battle axe, forged from adamantite and mithril, cut through the Balrog's skin time and time again, and blood splattered out like lava!

"Fight! Sons of Turin!" The blood-soaked Nene was like a god descending to earth! In that instant, the dwarves even suppressed the Balrog, pushing it back to the entrance of the hall. At that moment, they even felt that victory was in sight!
"Roar! Howl!" The Balrog roared furiously, unleashing a torrent of flames. In no time, its injuries had stabilized. The dwarves, however, were dumbfounded; they had never anticipated this scene...

But what did it matter? Countless dwarves fell, only to be replaced by newcomers. The dwarves fought with ever greater ferocity, growing stronger and fewer in number... Nien surveyed his surroundings, seeing only the corpses and remains of his kin. The entire hall was a scene of destruction, and fewer than a hundred dwarves remained alive. He sounded the war horn! The dwarves spontaneously gathered around him, staring at the Balrog dozens of meters away. Everyone knew that the final battle had arrived!