"Well the way I see it, clearly, I’ve gone apeshit insane. Or I’m in a coma having some fantasy dream or something— So, guess I might as well be the hero in it.”
Ben Grimm - 1610 (Ultimate) Universe bio
Ben Grimm is Reed Richards childhood friend and neighbor. He’s a star on their middle school football team, and looks out for Reed as best he can, chasing off bullies. He’s a regular face around the Richards house, hanging out with Reed and getting homework help from his young friend. He doesn’t often understand Reed’s designs and experiments, but he’s supportive and loyal regardless.
We don’t hear anything from Ben once Reed goes to the Baxter building, until he shows up at the test site in Nevada. Reed is 21 and Ben is presumably a few years older, but they’ve obviously kept in touch and Ben is overjoyed to witness his friends achievement.
Of course, things don’t go as planned that day, and Ben reappears in this dimension in Mexico City. He is Not Pleased with the way he’s changed.
Though troubled by the changes and their effect on his life (he’s not allowed out of the Baxter building for a good long while, and when he is, people are generally horrified by him), Ben does take some pleasure in being indestructible and having an excuse to hit things really, really hard.
Of the Four, Ben is the most unhappy with what’s happened, and Reed devotes himself (for a while) to finding a way to reverse what’s happened to him. In one prominent arc for the character, the team goes back in time to prevent the accident entirely, causing a cascade of events that leads to Earth being invaded by the Kree, with Ben (regular human Ben) the only one left to stop the invasion (Ultimate Fantastic Four #27-29).
Ben is the wiseguy and brute force of the team. He is not always terribly excited about the situations they find themselves in, but he’s fearless and fiercely loyal to his friends. Over time he befriends Johnny and Sue, although his relationship with Reed can be strained at times.
After Ultimatum, Sue and Ben deepen their friendship, being the only two of the Four remaining at the Baxter Building after the team falls apart. In Ultimate Comics: Doomsday (a trilogy of mini-series detailing Reed’s fall from grace) Ben seems to be, quite literally, falling to pieces, and undergoes a drastic transformation. He resumes his human form, with the ability to turn into a powered (glowy purple!) version of himself, where he retains his old powers of indestructibility and increased strength, while gaining a few more. We’re not told exactly what his new powers entail, but he is able to walk/break through Sue’s fields, and it is implied he is able to teleport. Sadly this new form has not yet been explored any further.
Ben is currently engaged to Sue Storm, and has taken on a job as a test pilot with the military. Though Sue has been appearing in recent Ultimate Comics: The Ultimates issues, Ben has not appeared since the end of Doomsday (Ultimate Doom #4). However, a new author on the series has stated his intent to bring Reed Richards back into play as a main character, so it is my hope we will be seeing more of Ben and the others in future issues, as the Four no longer have their own ongoing series.
Ultimate F4 Bio (with links to other character bios)