Hayako Sakurai is a brilliant Japanese scientist and one of the main characters in Endless Ocean: Blue World. She is a renowned marine scientist known for her broad knowledge of various different complex fields of study.
"Hayako comes from a well-known family in Kyoto, and her ferocious intellect has allowed her to earn PhDs in such disparate fields as mechanical engineering, ecology, marine veterinary science, and archaeology, even though she is only in her early 30s. Like many geniuses, she tends to jump from one topic to another and can be a little too candid, which tends to make others a bit uncomfortable. She also loves celebrity gossip."
Coming from a famous family, Hayako is viewed as a genius, holding Ph.Ds in mechanical engineering, ecology, marine veterinary science, and archaeology, and is the current professor of the Aquarium, all of which despite being only in her early thirties.
She befriends GG, Oceana and Jean-Eric Louvier during the story, and develops a strong friendship with the player. She advises him or her with their dolphin training, assessing the dolphin partners to monitor their progress. Passing her assessments allows the player to teach his or her dolphins more advanced tricks, while also unlocking the ability to accept dolphin show requests.
Hayako is depicted as a rather mature, calm and collected woman with a slight sense of humor. She is the only major character in the game to not show visible distress, and her down-to-earth nature allows her to act as the voice of reason during group discussions.
Highly intelligent, Hayako is a highly educated oceanographer. She knows all about most known marine life, and is often the one to point out fun facts about various species. Befitting her occupation, she is always studying animals and looking for new ways to answer scientific questions. She is also an experienced diver and even knows many ancient languages, which proves useful in finding the Pacifica Treasure.
When diving with Hayako, she grants the ability to locate and name any creature within nearby map tiles. The name of creatures is shown and any place the creature is located will be represented by a small red dot. Any creature that is not registered in the Marine Encyclopedia will be named ???. This ability does not, however, allow the player to find any creatures under zoom-mode glow spots. She can also let you see any scenes that you have unlocked in that area.