Grim Haunting is a story written by Sora Junko and illustrated by marourin. It ran in Issue 12 at http://s2b2.livejournal.com/61274.html, and is mirrored at http://www.shousetsubangbang.com/mirror/grim-haunting/.
Please note that this is the second story in the Grim series. You may want to go read the first one before reading this one, but this story does stand on its own.
- pinboard.in: "More Grim & Sebastian! I love how he invites himself in. Nice trick."