The guard that Hayato was fighting died from the beating it took from his sword.
Guard2: It seems these mortals are stronger than they appear... No matter, destroy them both!
The remaining two guards activated their staffs, and charged at Hayato and Sayuri, but one of them spotted the tidal wave
Guard3: It seems that we're about to be destroyed ourselves.
[Can you guys kinda please stay on topic?]
One of the guards were instantly drowned and killed, but the other one survived. It took out some sort of communication orb, and spoke into it.
Dark Guard: Lord Mardiir... They've beaten us... What shall we do now?
Mardiir: Release the Dark Serpant on them.
Dark Guard: Yes, my lord.
It put the orb away, and summoned a ball of Dark energy. Throwing it into the ocean, a swirling vortex of water formed and an enormous black sea monster emmerged from the vortex.