Gene Nation, a group of Morlocks whom Storm encountered and relocated to Africa. Boost was a mutant who functions like a living battery cell. He can augment other mutants' powers by a process called "body-jumping", wherein Boost merges with the other mutant and boost's their powers.
When the Humanity's Last Stand attacked the former Gene Nationals at their new home, Storm and the X-Men arrived to help. Unfortunately, so did Havok's Brotherhood of Mutants who offered the mutants protection against their enemies. Humanity's Last Stand were eventually defeated, and Boost, along with fellow former Gene National Tether, sought to leave, helping the Brotherhood escape in return for being dropped off at an unrevealed place of their choosing.
Boost was affected after the Decimation, and lost his mutant powers.