Benjamin J. Grimm has a publically known identity as The Thing of the Fantastic Four. Given he's well over six feet tall and made of rock, figuring out where he is and who he is is rather easy. Ben is the 'big uncle' of the family, protective to a fault, and also the most down to Earth of them. His constant moping due to his alienated nature are his defining traits.
Ben was born to a family in Manhattan's Lower East Side, where his family grew up in heavy poverty, a group of Jewish immigrants who had come to New York after WW2. Ben's father, an alcoholic, could not support his family. Thus, Ben's older brother Daniel was the one who supported the family, primarily by illicit activities done with the Yancy Street Gang. Daniel was idolized by Ben, and Ben was devastated when his brother died in a gang fight when he was eight.
Ben joined the Yancy Street Gang, rapidly becoming one of the leaders of the gang. He was eventually adopted over by his father's brother Jake, who was of a somewhat better economic class. Ben was resistant to being raised by his Uncle, who was eventually able to get Ben to realize that his Uncle loved him, and Ben warmed to the family. In high school, Ben got into sports, seeing it as a way of getting out of the streets and making something of himself. He got into a private high school on a football scholarship, having a reputation in the city leagues as 'The Grim Reaper' for his ability to make tackles.
After high school, Ben was at a crossroads. He wanted to go on to college, but even skimping together his savings and possible scholarships couldn't afford it. So, Ben decided to join the air force and work his way up and get a military scholarship. Ben did well in the military, despite his lack of having a college degree, making it through courses in the military on little more often than raw stubbornness. The structured lifestyle did him well, and Ben eventually came to serve as a combat pilot, getting his wings and spending several years in the air force before deciding to take some time off to go to college.
In college, Ben was somewhat of a stranger, being several years older than most of the students. Having a reputation as a jock, but a quiet one, Ben was roomed with an archetypal 'nerd' student, Reed Richards. The two could hardly be considered to be more different than one another, but they got along incredibly well. Ben helped keep Reed grounded and sociable, and was protective of the younger man. Reed, in turn, helped Ben study and gave him dreams of the future. One time while drunk Ben made a promise to Reed if they ever went into space, Ben would be the one to fly them up. They laughed about it the next day.
After college, Ben returned to the military and spent some time flying again. When he was contacted by Reed Richards, who was wanting to take his new, untested spacecraft to fly to the stars and needed a pilot. Ben thought the craft wasn't safe, but a promise was a promise. And Reed convinced him to go along, and Ben helped ready the craft and was trained to fly it.
Along with Reed, the crew included Johnny Storm and Sue Storm. As they flew into space, the craft's radiation shields failed as the craft was bombarded with a heavy dose of cosmic rays that hit the craft unexpectedly. They crash landed back on earth, having taken heavy doses of radiation. As they pulled themselves from the crash, each discovered they had developed new, amazing powers beyond those of mortal men. As the others discovered their abilities, Ben discovered, to his horror, he was turning to a monster. A man made out of rock. Horrified, Ben was talked to helping the others in turn for Reed promising he would do everything in his power to turn Ben back. Taking on a name from his monstrous form, Ben would hereafter be the THING!
The Fantastic Four become the first superheroes of the modern era of New York of the Marvelverse. The 'First Family' of heroes, what differentiates them is that they have public identities and are open to the public in the Baxter Buliding. Their early adventures involve fighting the Mole Men, and encountering the Skrulls while in space. They move to the Baxter Building, and have to constantly fight to get enough money to stay operational.
Ben does not get along with the rest of the team, particularly Johnny, the youngster's pranks constantly alienating him. Ben is hit hardest when he tries to go home to Yancy Street, and is regarded as a freak by his old friends who ran away and abandoned them.
Ben searches for someone who can accept him, eventually forming a halting relationship with a blind woman, Alicia Masters, who in turn sets the team to facing off with her stepfather, the Puppet Master. Ben's relationship with Alicia would continuously be rocky, the two always on amiable terms with one another, even if not romantically involved.* The Fantastic Four have numerous adventures while fighting their enemies, encountering the villainous Doctor Doom, the anti-heroic Namor, King of Atlantis, and via the amazing technology of Reed Richards, encounter such far flung adversaries such as Blastaar of the Negative Zone, and the time traveling villain known as Kang. They also team up with other heroes beginning to populate the new Earth, and many of the old ones, forming a strong association of friendship with groups such as the Avengers, and street level heroes such as Spider-Man after his aborted attempt to join them.
At one point, the Fantastic Four were captured and replaced with Skrulls, only to be saved when the heroes known as the Avengers realized the switch and rescued them. The danger of having heroes replaced by Skrulls would be a long term nightmare of all heroes throughout Earth. The Fantastic Four would continuously brawl with their enemies, barely defeating Doctor Doom on numerous occasions, or the dreaded Super Skrull, sent to Earth to gain revenge.
Perhaps their most frightening experience as a team was in facing off with the Devourer of Worlds, Galactus, and with the help of the Silver Surfer and the Watcher saving the Earth from his consumption. Shortly after this, the heroes of Earth face off with the Champion, an extra-galactic martial artist in possession of the Strength Gem. He fights the heroes of Earth in a staged boxing match, and Ben matches him blow for blow, refusing to back down. Even when faced with the fight continuing to his death, Ben would not stop. The Champion is suitably impressed by Ben's steadfastness and allows a draw in the match, finding Ben the worthy adversary he sought.
The Fantastic Four meet new, strange enemies and allies from space, encountering the mysterious Inhumans on Earth's moon. They form bonds of friendship and feuding, fighting alongside and against them, but are steadfastedly on good terms with their leader Black Bolt. Among such brawls they have on Earth are with the Frightful Four, the Fantastic Four's darker counterparts.
The Fantastic Four fight many more adversaries, both Earthly and from the cosmos, generally on good terms with all. Life goes on, until the sudden merging of the Crisis. Ben himself is transported to the desert world, wandering for days on end in searth of other friends or allies, finding none. The period of long wandering increased his sense of alienation, finding only things wishing to consume him. Right before Ben is broken by his self-pity, the Crisis ends and the heroes' worlds become one. Then Ben has to face with a new world with things that are unknown. New cosmic enemies, new adversaries,and new allies. But the Fantastic Four will be ready to face them. For they are family.
Down to Earth: Ben has to play up the role as the straight man with the Fantastic Four. In all the absurdities, the weirdness that surrounds the team, Ben has to be the one to keep them connected to the streets of the city below them. He's the rational one, the calm and collected one, who plays the straight man to the rest of the team's foibles. And the one who reminds them that sometimes just the simplest and most direct route is the most effective one.
Protective: Ben is protective of the rest of his team. For all the fuss they give him, for all the sass he shoots back, he is the papa bear of the group. Woe behold anyone who tries to harm them. They'll have to go through him first. Even with Johnny - Ben's the only one who can put the kid in his place, but he's Ben's to put in his place. Ben is perhaps the most protective of Reed, for all the two have gone together, and even while he vociferously disagrees with him, Reed is still his best friend, and he'll go to the ends of the Earth for them as the 'grouchy uncle'.
Steadfast: Ben will go up against anyone and anything anytime. They might hit him hard, but keeping him down is nearly impossible. The only way to stop Ben is to kill him. He's a bulldog, once he has his teeth set over in something, he won't let it down or back it off. Ben will keep on going no matter the circumstances until the other person breaks or he does. He's loyal and strong to a fault, and nothing's going to wear him down. He's made of rock after all.
Alienated: Ben is in his own way distant, both from his home and from other people. He feels very much his role as the monster, and dealing with all the reprecussions that has entailed. Ben truly wants to be human again, but he knows that if he does become human it will involve giving up his role on the team, and he can't abide that as it means he can't be there to save his friends anymore. Ben is the strongman, but he struggles most with his own issues at loss of his own humanity and his acceptance among people. For all the support his friends give him, all the acceptance he's had from the population at large, Ben truly feels alienated from himself, and this has been his greatest struggle at overcoming. The sense that he is not a man, he is a monster.
Social: Ironically, Ben is probably the most sociable of the team, and has the most sense of connection to the community. He's the one who cleans up after Johnny. He's the one who makes sure Reed takes care of himself. He's the shoulder that Sue cries on. Ben is the strongest connection the FF have to the outside world of humanity and to the superhero community at large. He'll always be on his old stomping grounds of Yancy Street. He'll always be on call for other friends if they need a hand. But he'll also be the one to call up on other heroes to check how they'll be doing, invite them to parties, or otherwise be hanging out on the streets if needed. The irony of how the self-proclaimed monster is this is lost upon Ben himself, if not to everyone else.