Here's a list of how to defeat some of the Tsunami enemies.

Revenant Beast:
This slow-moving monster has a strong body. You cannot cause damage to it under normal circumstances. You need to let it attack. After it attacks three times, it will fall into a very long state of fatigue, and then you can kill it.

Durga:
Its black core is hidden inside and protected by its multiple limbs, just attack that core. (When it attacks, the core will be exposed).

Brzaka:
You can consume its cellular energy by attacking it or letting it attack. When its energy is exhausted, it will enter the energy storage state. This is your chance to attack it.

Shark:
You need to attack its belly, as it can easily become invulnerable after being attacked.