Manu Noonien-Singh was the 23rd century Human son of Sa'An and Ronu Noonien-Singh, and elder brother of La'An Noonien-Singh. He was also a descendant of the infamous Khan Noonien Singh.
He was with his family aboard the SS Puget Sound when the colony ship was captured by the Gorn. They were taken to one of the species' nursery planets, where he was subsequently killed. (SNW: "Strange New Worlds")
Prior to his death, he was able to determine how the Gorn communicated with flashes of light, and created a small book he gave to La'An with the key to their code, a memory La'An had initially repressed. It was later recovered through a mind meld with Spock, where the two both briefly experienced memories regarding how their respective siblings — Manu and Spock's sister — had sacrificed themselves for them. (SNW: "Memento Mori")
After encountering Gorn hatchlings on the USS Peregrine, La'An again remembered her brother telling her to run and told Oriana that the Gorn had gotten her brother like they did Oriana's friend "Buckley." (SNW: "All Those Who Wander")
After being captured and brought aboard a Gorn destroyer, memories of her family awakened La'An in her pod and continued to haunt her as La'An moved throughout the ship. La'An was able to recall how her brother had accessed a Gorn interface on the breeding planet and used it to access the systems of the destroyer and steal the Gorn transporter codes needed to save the Parnassus Beta colonists. (SNW: "Hegemony, Part II")