Builders (Earth-2042)

The Builders, referred to in some formal contexts as the Builder Corps, were the highest rate of the Forerunners, considered to be the most powerful in terms of intelligence, wealth, and political power. As their name suggests, the Builders were responsible for designing and constructing the majority of the Forerunners' advanced technology, including starships, weapons and the myriad of technologically advanced structures and objects seen throughout the galaxy, most notably the Halo Array. The chief of the Builder rate and all its guilds was known as the Master Builder. The last Forerunner to hold this title was Faber.

Source

 * https://www.halopedia.org/Builder