Short answers, pulled from the story.
Role-playing video games originated in the mid-1970s on mainframe computers, when developers attempted to implement systems like Dungeons and Dragons on PDP-10 and Unix-based systems. Early titles included text-based games like Dungeon, pedit5, and dnd. The first notable RPG on a microcomputer was Dungeon n Dragons, written by Peter Trefonas and published by CLOAD in 1980 for a TRS-80 Model 1.
Western RPGs tend to feature darker graphics, older characters, open worlds, and a greater focus on player-created characters and underlying game rules. Japanese RPGs tend to feature brighter, anime-influenced graphics, younger characters, and tightly orchestrated linear storylines. These differences trace back to the 1986 Dragon Quest on the Famicom, which simplified the RPG format to fit console hardware and became the template for Japanese console RPGs.
Final Fantasy VII was released in 1997 with a record-breaking production budget of around $45 million. The game introduced innovations including 3D characters on pre-rendered backgrounds, battles viewed from multiple angles, and full-motion CGI video integrated throughout gameplay, raising the production and storytelling ambitions for the entire genre.
A roguelike is a subgenre of role-playing games characterized by procedural generation of game levels, turn-based gameplay, tile-based graphics, and permanent death of the player character. The subgenre is named after the 1980 game Rogue, which used ASCII characters to represent the setting, monsters, and items. Notable variants include NetHack, Hack, Ancient Domains of Mystery, Angband, and the Japanese Mystery Dungeon series by Chunsoft.
The experience point system, the most common progression method in RPGs, awards points called XP or EXP for winning battles, completing quests, and performing class-specific activities. Once enough experience accumulates, the character advances a level and gains new abilities. Some games level up characters automatically at the required threshold; others let the player choose when and where to advance.
The MMORPG genre developed from graphical MUDs in the mid-1990s, beginning with Meridian 59 in 1995 and Nexus: The Kingdom of the Winds in 1996. Later titles including Ultima Online in 1997, Lineage in 1998, EverQuest in 1999, Final Fantasy XI in 2003, and World of Warcraft in 2004 expanded the audience significantly. Secret of Mana in 1993 was one of the first commercial RPGs to feature cooperative multiplayer gameplay.