Edward Richtofen is the German scientist from Treyarch's Call of Duty Zombies storyline, first appearing in World at War in 2008 and becoming one of the mode's most quoted characters. Caro diario is Italian for dear diary, and the nota vocale description points to how this version circulated in Italian-speaking gaming communities as a short voice-note style joke. Fans repost impressions and edits of Richtofen in mundane formats because his grandiose delivery makes even a simple diary greeting sound like a secret experiment log.