Short answers, pulled from the story.
Music experts credit Run-DMC as the first hardcore hip-hop group. Other early pioneers include Schoolly D in Philadelphia, Too $hort in Oakland, Boogie Down Productions, and Public Enemy, whose confrontational lyrics and chaotic production style set new standards for the genre.
Hardcore hip-hop is characterized by anger, aggression, and confrontation, and generally describes violence or anger in its lyrics. The genre encompasses both gangsta-themed content and progressive political themes, with artists like Public Enemy and KRS-One incorporating revolutionary lyrical content.
Gangsta rap is generally considered a subgenre or offshoot of hardcore hip-hop, not a synonym for it. Not all hardcore hip-hop revolves around gangsta lyrical themes; Russell Potter noted that hardcore rappers have laid claim to a wide variety of ground beyond the monolithic gangsta outlook the popular press often ascribes to them.
Hardcore hip-hop originated as a largely East Coast phenomenon in the 1980s, but by the late 1980s it became increasingly synonymous with West Coast gangsta rap as artists like N.W.A infused gritty gang life stories into the hardcore style. In the early 1990s it shifted back to the East Coast with the emergence of Wu-Tang Clan.
Wu-Tang Clan emerged in the early 1990s and brought hardcore hip-hop back to its East Coast roots with minimalistic beats and piano-driven sampling. Their sound became widely popular among other hardcore hip-hop artists of that era.
Punk rap is a form that emerged in the 2010s, combining elements of hardcore hip-hop and hardcore punk. Denzel Curry was among the artists at the forefront of the movement, extending the confrontational traditions of hardcore hip-hop into new sonic territory.