Brad Boimler's transporter duplicate, who stayed on the Titan, joined Section 31 and later captained the Anaximander.
William Boimler is a duplicate of Brad Boimler created by a transporter malfunction aboard the USS Titan. To keep the two apart, Brad was sent back to the Cerritos, while the copy remained on the Titan under Captain William Riker and took the name William in Riker's honor.
William later faked his death and joined Section 31. He resurfaced as captain of the Anaximander, a Defiant-class ship hunting the source of dangerous interdimensional rifts, crewed by alternate versions of figures such as T'Pol, Elim Garak, Julian Bashir, Curzon Dax and several Harry Kims.
When the rift source exploded and threatened the multiverse, William directed the energy wave into his own universe and sent a warning to his counterpart, trusting Brad and the Cerritos crew to find a solution.