After you activate the water spouts in Jabul Ruins, you go through the Big Door and battle Vocavor.

How to Defeat Vocavor

First Phase

Throughout the battle, be sure to swim in front of the bubbles from time to time, to make sure that your dive meter doesn't run out.

Vocavor will send small whirlwinds toward you. Stay near the bottom or top of a whirlwind so it goes past you, then go up or down to dodge the next whirlwind.

After Vocavor finishes creating whirlwinds, it is temporarily stunned. Hit the glowing orbs on its back, or pull them off with bind, to destroy them. Remember to hold ZL to target the orbs to make them easier to hit or bind to. The orbs drop energy and hearts when destroyed. Then its back will flash. Hit its back repeatedly at this time, either with swordfighter form or with a monster echo. But when its back isn't taking damage anymore, swim out of the way, because Vocavor is about to do a spin attack.

Vocavor will sometimes launch the spikes from its tail. They will keep moving slowly toward you, then they will start to flash, and after a short time, they will explode. Swim away from them until they are gone.

Second Phase

After you hit Vocavor enough times, the water in the middle will become lower.

Vocavor will go to one side and make whirlwinds like before, but after the third whirlwind, Vocavor creates a much larger whirlwind in the lower or upper half of the screen. After this large whirlwind, Vocavor will flip upside down. Get underneath Vocavor and hit the glowing orbs on its back. After a short time, Vocavor will do a spin attack, so move out of the way.

Sometimes Vocavor creates whirlwinds in different patterns, such as on top of each other with a narrow gap in the middle, so watch carefully for safe locations to dodge them.

In addition, sometimes Vocavor will turn its back to the side instead of turning upside-down, so be ready to swim to the correct location to attack the glowing orbs on its back.

When Vocavor sends the spikes from its tail, you can avoid them by going to the other side of one of the platforms so that the spikes crash into the platform.

Repeat the above strategies until the battle ends. There will be a cutscene. Tri's gauge will increase. If Tri reached Lv. 4, certain monster echoes will use fewer triangles. You receive 5 Might Crystals.

Take the Heart Container (or leave it there for more of a challenge), then go to the left and talk to Tri to exit the dungeon if you're ready. There will be a cutscene.

If you repaired the Gerudo Desert Rift, the next quest, Still Missing, will begin. If not, read The Path to Gerudo Desert to find out how to continue.