Mighty, older brother of White Bomber, left his home to fill in the spot of "Bomberman" in the group known as The Jetters. Very kind and mature, he served as the leader. He even developed the Sal-T Bomb and owns his personal hoverbike, the Moto Jetter.
He was very close to his younger brother, and taught him a lot of skills, most of which he would use later on when he (White) became a Jetter. These included using a feather (or White Bomber's "Balloon Bomb") to find their ways out of caves, to give up if you hate doing something (when White Bomber lost the baseball he, his brother, and friends were using for a game, Mighty told his brother that, if he didn't like baseball, then he wouldn't have to play it), and many other things.
One fateful mission on Bomber Planet, Mighty was badly wounded by a laser from a machine that Mujoe brought to intimidate the Jetters (this was purely accidental; the machine went haywire and the Hige-Hige Bandits couldn't stop it). However, he was convinced to do the following mission (to destroy a HigeHige HQ), and even went further, attacking the main base at the time, despite being near death. For the majority of the series (until episode 23), Mighty was thought to be missing in action, but Mujoe told Birdy that he was actually dead.
After Mighty was revealed to be dead, it was believed that Max was the one who murdered him. However, the "Max" that was seen at the time was actually Bomber Zero. Zero was built by Dr. Mechadoc to absorb Mighty's data, and that he did. Zero left Mighty who was unconscious, and when Mighty came around, he decided to fulfill his mission. In the final episode of the series, it's revealed that Mighty chose to complete his mission and to do so, had to face the impact of his own bomb, thus taking his own life.
For more information on Mighty after his death, see Bomber Zero.
The time he also died was in space, when White Bomber didn't notice it yet.