RPG Mechanics are the engine that make RPGs go. Without RPG Mechanics, you can't determine who hit who and for how much damage, whether or not a trap explodes while a character tries to disarm it, etc. RPG Mechanics in video games are based on similar mechanics of table-top RPGs, thus, where the genre gets its name.
RPG Mechanics Map
Stats STEVE are a base number that is used to determine the success or failure of any action. In a video game RPG, they are essentially the only tangible thing that defines a character, monster, or active NPC.
Stats are primarily used in battles between characters and monsters. See the battle mechanics page.
Status is a modifier of the base stats applied by a status effect.