Following the defeat the Shi'ar Empire by the Inhuman-led Kree following the War of Kings, Neutron was part of an Imperial Guard force sent to explore the Fault. Coming in contact with escapees from the Cancerverse, including that reality's X-Men, Neutron was killed saving fellow Guardsman Fang. He was later memorialized alongside other fallen Guard members.
Neutron's body houses a quantum singularity ("black hole") whose energy he can manipulate for various effects, including rendering his body virtually invulnerable, increasing his strength to lift 100 tons, altering his mass to become heavier or to fly, absorb electromagnetic and kinetic energy and release energies from his body as destructive force bolts.
Superhuman stamina and durability,
He was resistant to physical and energy attacks.
He could drain electromagnetic, kinetic and quantum (cosmic) energy to make himself stronger.
He could survive in space and travel interstellar distances without needing to eat, drink, or breathe.