The Grand Bastion is an impenetrable fortress that held the line for centuries and will continue to do so for centuries to come.
The walls are made of huge bricks and reinforced with Steel. They have overhangs high above the ground, where crossbowmen and archers can stand and shoot at attackers clawing at the walls below.
The pinnacle of human enginuity - as deadly as it is complex. The napalm throwers are large static canons that use pumps to compress flammable liquid from large tanks and shoot it out at high pressure - sending a stream of flame that sticks to everything it touches.
In the middle of the city and at the edges are many Balista towers, meant to shoot down big aerial threats and Massive lumbering targets on the ground. With their size being close to 100 feet and their projectiles heavy enough to have to be loaded by cranes - they are able to tear apart a Wyrm in a single shot.
Near the edges of the walls there are numerous catapults, operated by crews of several infantrymen - shooting heavy boulder projectiles filled with explosives at enemies below.
In the middle of the city there are a couple of collosal trebuchets, reaching 300ft in height. They are crane loaded with fittingly collosal boulders filled with unfathomable amount of explosives, able to send them miles away - used to target large clusters of enemies approaching the walls, with the explosion turning the boulder into a grenade that sends lethal shrapnel hundreds of feet around.