It became clear, almost immediately, that the capital had suffered some kind of blast. The way that the tunnels had collapsed, the way the walls were charred, and the way that the rubble had fallen made it apparent that someone had dropped a bomb inside the hole and then had blown it up.
Fortunately, or unfortunately, this seemed like the explosion wasn't recent. There were clear signs of repairs to a few tunnels, and of Kraven moving through them. It seemed like this place had been evacuated since the time of the explosion.
But just because the place was abandoned did not mean Lex lowered his guards. He felt a subtle warning from his instincts letting him know that there was some kind of hidden danger in this place. Considering that this was the former capital of the race invading a whole realm, it would be surprising if it was just left alone.