More than any genre since the blues, gangsta rap is a musical form forged out of pain. The root causes of this foundational pain were broadly the same for both genres – poverty, racism, crime, deprivation – and for both, what started as expressions of genuine suffering soon hardened into conventions, postures, and tics. When Robert Johnson sang of the hellhound on his trail in 1937, he sang it like a man haunted and hunted by very real demons. When Fleetwood Mac covered the song in 1968, the lyrics had become empty signifiers, relics of a bygone mythology. In gangsta rap, the evolution was both quicker and more complex.

Gangsta rap has always grappled with a central contradiction: It can function as the most searing sort of protest music, steeped in pain, pride and defiance. And it can also serve as a form of vicarious escapist entertainment, comic-book crime tales and violent power fantasies ready-made for listeners who have no idea what it’s like to grow up in fear of batterams or drive-bys. That tension was already coming to a head in the mid-1990s. Though still endlessly controversial, gangsta rap was nonetheless transitioning into just another strain of pop music, with profane yet irresistible anthems from Dr. Dre, Snoop Dogg, and the Notorious B.I.G. soon to become staples of frat parties and wedding receptions.

It was into this incongruously sunny, West Coast-dominated environment that Mobb Deep’s 1995 breakthrough album “The Infamous” arrived like a dark, heavy cloud.

Led by the diminutive yet imposing Albert “Prodigy” Johnson, who died yesterday at the age of 42, Mobb Deep never seemed interested in meeting its audience halfway. If Snoop was offering mainstream listeners “Gin and Juice” and Biggie “Party and Bulls–t,” Mobb Deep responded with “Drink Away the Pain” and “Party Over.” Barely out of their teens, both members of the group had already established the formula from which they would scarcely deviate for the rest of their careers: Creaky, homemade haunted house beats largely created by Kejuan “Havoc” Muchita, and blood-curdling lyrics that seemed to be the product of decades of strife and trauma, none more finely crafted than Prodigy’s. “I got you stuck off the realness,” Prodigy raps at the start of the duo’s signature track, “Shook Ones (Part II),” but when he adds “I’m only 19 but my mind is old” a few lines later, you’re tempted to consult the fact-checkers. Nineteen? With his stoical, effortless delivery and shell-shocked cynicism, he might as well have been 90.

More than just one of the greatest hip-hop albums ever released, “The Infamous” was a single-minded masterpiece of pitch-black pulp art, and few lyricists, within hip-hop or without, were better at conveying the sadness, horror, and pointlessness of violence than Prodigy. Of course, he was far from a moralist, and his nihilistic first-person narratives sometimes bordered on the reprehensible. Like Cormac McCarthy in a black bandanna, he luxuriated in the morbid details, the casual threats, the cold aura of violence – if there was condemnation to be found, it was purely extra-textual. But there was never anything celebratory in Prodigy’s grim tales. They were all miniature tragedies, drenched in exhaustion, paranoia, and loneliness. Again and again on “The Infamous,” he offers little glimpses of just how avoidable, petty, or self-created so many of his brutal conflicts really are. “It was a small thing, really,” he shrugs on “Eye for a Eye,” explaining why he shot a rival dealer over a negligible amount of drugs. “To the kids, you don’t wanna be me,” he warns on the album’s opening track, and asks for God’s protection as he strides “into the drama I built” on the second.

On the album standout “Cradle to the Grave,” Prodigy’s war is lost before it’s even begun. “I swore our crew would live forever, I guess I was wrong,” he raps, before going on to explain a plan to murder an unnamed neighborhood associate for some unspecified offense. Most rappers would describe the adrenaline rush of the crime itself, but Prodigy skips it entirely, instead giving us the anxiety of the plotting, the waiting, the queasy subterfuge as he makes the rounds “acting like everything is alright.” He can’t even head to Brooklyn to meet a girl for a date on “Trife Life” without worrying that she’s setting him up for an ambush. “Maybe I’m blowing this s–t out of proportion,” he wonders for a moment, but brings backup along anyway. A life of crime has rarely sounded more miserable.

Of course, realness cuts both ways, and Prodigy’s personal life was more complicated than the character he played on wax. He grew up around some of Queens’ roughest neighborhoods, and while there’s little doubt his lyrics were informed by harrowing first-person observation, he was nonetheless raised with a certain degree of privilege, and was heir to an illustrious family history. His mother had been a member of 1960s girl-group the Crystals; his grandmother ran New York’s famed Bernice Johnson Cultural Arts Center dance studio; and his great-great-grandfather founded Morehouse College. In other words, he seemed to have every potential to pursue a more comfortable life, free from the horrors of the streets.

With one enormous exception: In his arrestingly vivid 2011 memoir, “My Infamous Life,” Prodigy describes his early life as a sufferer of SS type sickle cell anemia, which would later cause his untimely death. He recalls regularly waking up feeling as though his bones had been broken while he slept. He spent weeks out of the year in the hospital. He contemplated suicide. He was too frail to play sports as a child, and remembers kids on the school bus gawking at him as he slowly limped his way to the door, knowing that even walking too fast could land him back to the ICU.

“There’s no conventional medical cure for sickle cell,” he wrote. “The only treatment was high doses of strong pain medication like Tylenol with codeine as a child or Demerol or morphine as I got older, the stuff they give soldiers when their limbs are blown off in a war. Hospitals only allow doses every four hours, but I had a high tolerance for the medication because my pain was greater than most people’s. After an hour, I was screaming again.”

It’s impossible to appreciate the depth of Prodigy’s art outside of this context. It explains his bone-deep cynicism, his fetishization of violence, his refusal to let any slight pass unanswered. (His feuds with Tupac and Jay-Z have been written into hip-hop lore, but they were merely two entries on his lengthy enemies list.) His lyrical exploits may have been fictional, but the trauma beneath them couldn’t have been more genuine. Pain was never an abstraction for him, and the realness stuck. Prodigy’s hard-boiled persona may have been compensatory – on the microphone, he could project the sort of indestructibility that his body never allowed him – but he was too intimate with suffering to glamorize it. If other hardcore rappers seemed to model themselves on Clint Eastwood’s Man With No Name, Prodigy cast himself as “Unforgiven’s” William Munny: battered, beaten, and predestined to return to his own worst ways no matter how badly he wants to stop. But within this sad fatalism, there was a kind of strength.

The last time I saw Mobb Deep live was in 2011 at the House of Blues, shortly after Prodigy was released from a three-year prison bid. (His memoir had just been published, making this the only concert I’ve attended where the merch table was dominated by stacks of books.) The duo were every bit as ferocious, irritable, and antagonistic onstage as you could hope for, and during the encore, I witnessed something extraordinary. Just to my right, a thirtysomething man had spent the entire show parked in a wheelchair, slowly nursing a single drink. When the buzzsaw squeals of “Shook Ones” first rang out, I noticed the man stirring. With a few careful lurches, he lifted himself up out of the wheelchair, planted his feet hesitantly on the ground, and stood up, hoisting his drink into the air for the duration of the song.

I have no idea who this man was, why he was in a wheelchair, or how much it must have taken out of him to stand up like that. But I do know this: He probably understood Prodigy more deeply than I ever will.