Kiryu is the incarnation of Mechagodzilla introduced in Godzilla Against Mechagodzilla in 2002 and returning in Godzilla: Tokyo S.O.S. in 2003, a cyborg weapon built by the Japan Self-Defense Forces using the bones of the 1954 Godzilla. Its roar became a favourite among kaiju fans because it mixes the classic Godzilla bellow with grinding metal, making it distinct from the organic roars of other monsters. Short clips of the sound now circulate in edits, fan films and soundboards whenever a mechanical monster needs an instantly recognisable voice.