How to Get the Water Guy in Zelda

Remove the Twilight veil over the Lanayru province by catching all of the light bugs in the area. This is done just as you did in the two previous provinces to remove their Twilight veils. Find the spirit shrine, located along Lake Hylia and receive a map of where to find all the bugs and hunt them down in your wolf form. The final insect is a boss monster floating in the lake. To defeat it, stun it with a lunge attack and jump onto its belly. Use your dark magic attack to damage all six of its legs at once. When defeated, Lanayru province will return to normal.

Visit Telma at her bar in a back alley of Castle Town. Once the Twilight is gone, return to the bar and talk to Telma, who is tending to a wounded Zora child and desperately needs to get him to a doctor. The ghost of the child's mother will also appear to you and promise you a reward for helping her son.

Escort Telma's wagon to Kakariko Village in the Eldin province. You will need to first cross the Hylia bridge which is guarded by King Bulbin. He is armored on his sides, so you will need to charge your horse straight at him and fire arrows at his chest. Once defeated, follow the wagon and protect it from attacking riders and birds. Use your bow to attack foes from afar or your sword if they get in close. If the wagon catches fire, your gale boomerang can extinguish the flames. Keep guarding the wagon until it enters the gate to the village.

Take the child to the village healer and receive your reward. Once the child is safe, his mother will appear to you again, beckoning you to follow her. She will lead you behind the village graveyard and open a special grave that leads to a cavern. In the cavern, you will find the Zora Armor. With it, you can now breath underwater and enter the Lakebed Temple.