After the fire oil solidified, the ground was covered with grass and trees, making it look nothing out of the ordinary. Kill all the scouts who try to enter this area for reconnaissance, and use the stench of hundreds, perhaps thousands of rotting corpses to mask the pungent smell of the fire oil.
After the battle begins, and when the Tuling Tuo Army rushes to the bottom of the city walls where the crowd is densely packed, a single spark will turn these tens of thousands of square meters into a fiery hell, certainly causing the Tuling Tuo Army to suffer countless losses amidst ghostly wails and wolfish howls.
Exchange astronomical amounts of supplies for the least amount of casualties and the greatest victory.
In terms from Earth, that's using a thousand bullets to kill one enemy.
Bury you with money, bury you with countless bullets and shells!
Now in the Rage Wave Kingdom, only Suo Lun can afford to fight such a war!
...
"Giant Crossbow Battleground, advance!"