Han Fei had been focused on the battlefield.
He did spread his senses underground at some point, but he didn't find anything under his feet.
After that, he focused all his attention on his teammates.
At this moment, after he spread his senses again, Han Fei found a great number of Big Sword Water Fleas that were popping up.
It further suggested that this was an organized attack, and not that the crabs wanted to lay eggs on the shore.
However, the number of the Big Sword Water Fleas was much smaller than that of the Tide Calling Crabs. Now that someone had noticed them, everybody released their perception.
Still, their pressure was increased as they had to defend against enemies on and below the ground.
The guardians reacted fast enough. Hardly had the shadows of big swords emerged when purple smoke was released from the watchtower and the alarms were sounded again.