The circus had chosen the Hydatoncus Mountains of the Old World as the venue for this performance. Also known as the Tumor Mountains, the name said it all—the mountains resembled tumors.
Since they were tumors, they were naturally connected to the Cancer Palace. However, the mountains lay extremely far from the Cancer Palace, and even the Black Roundworm Train took more than two days to get there.
Moreover, the Tumor Mountains had not existed since ancient times. They had formed during the invasion war that had altered the Old World's structure and caused the rules to be sealed away.
At the time, a thirty-man squad of Tumor Knights had deliberately lured the enemy here to buy time for the main force. They had fought bitterly for two days and three nights, far exceeding the expected delay, but the knights had also been completely surrounded, leaving them no chance to escape.
In the end, all the knights had chosen Cancerous Self-Detonation. Even in death, they intended to annihilate as many enemies as possible.
After detonating the Pathogen Core known as "Tumor," the knights' bodies immediately underwent irreversible hyperplasia. The wildly spreading tumors instantly occupied the surrounding area, devouring the enemy's flesh and eventually forming thirty tumor-shaped mountains.
After the war ended, the Cancer Palace had sent people to mourn the thirty brave and resolute Tumor Knights. A memorial monument was built at the foot of the mountains.
As time passed and the Old World gradually recovered, the Tumor Mountains unexpectedly developed into a famous tourist attraction.
A small town beside them had also rapidly developed through tourism. It had now become a fairly large neutral city, renamed Tumor City from its original name, Kashi Town.
Its most famous product was "Knight Mountain Spring."
The spring water collected from the Tumor Mountains