Mermaids were very weak in combat when they had no water to control, but as long as they had enough, they would become the most terrible enemies.

Mermaids were born to have an extremely great control over water elements, and the moat of The Rising Sun City became the basis of Xi Yan's counter-attack.

The Aqua Sea Wave Prison did not do much damage by itself. Its real strength lay in the confinement of the enemy. As long as water could be continuously supplied, the water prison would never be broken.

Xi Yan knew that she wasn’t very strong, and that her attacks would be almost negligible for the devil generals, so she poured all her power into the imprisonment of the enemy. This was Xi Yan's plan: to pin down Mu Tu, to prevent him from participating in other battles!