Short answers, pulled from the story.
John Romero is an American and Irish video game developer born on the 28th of October, 1967, in Colorado Springs, Colorado. He co-founded id Software and designed or co-designed Wolfenstein 3D (1992), Doom (1993), Doom II (1994), Hexen (1995), and Quake (1996), games that established the first-person shooter genre.
John Romero is credited with coining the multiplayer term "deathmatch," which describes a competitive mode in which players fight each other rather than cooperating against the game. He introduced the concept and the word during his time at id Software in the early 1990s.
Romero was forced to resign from id Software in 1996 following a conflict with John Carmack during the production of Quake. Carmack accused Romero of not contributing as much as the other developers; in 2022, Carmack told podcaster Lex Fridman that he regrets how he handled the firing, citing immaturity and a poor understanding of corporate structure.
Daikatana was announced in 1997 with a planned Christmas release that year but was delayed repeatedly and not released until April 2000. The game received poor reviews and appeared on multiple "top 10 worst games" lists. Romero publicly apologized for the game's infamous 1997 advertisement in a 2010 interview in Gamesauce.
In level 30 of Doom II, "Icon of Sin," the final boss plays a distorted demonic sound that is actually Romero's own voice saying "To win the game, you must kill me, John Romero!" reversed and altered. Players who used the noclip cheat could find Romero's severed head on a post inside the boss; his head functions as the enemy's hit detection point.
John Romero's autobiography is titled Doom Guy: Life in First Person, published in 2023. In it, Romero confirmed that the FPS Blackroom was fully cancelled after a behind-closed-doors demo failed to attract a publisher, following the Kickstarter campaign's cancellation four days after launch.