A Monument to All Your Sins is a campaign achievement in Halo: Reach. This achievement is obtained when a player completes every campaign mission in Halo: Reach on Legendary solo. It is represented by a Legendary symbol with a human skull rather than the traditional Sangheili skull. [b]Just Noticed this little egg and thought I'd share it. [/b] [b]I remember how insanely difficult getting this achievement was... It was totally worth it XD[/b]