For some reason the Grim Repeater seems to really like picking on the male (so far) cast of Babylon 5, a science fiction series that ran five seasons from 1994-1998. Despite ending less than twenty years ago, over half the main male cast are now deceased (six out of ten), as are over half of all cast members who were in all five seasons (four out of seven). Here is the chronology of cast members passing. Only actors in the opening credits noted. While Tim Choate was great as Zathras, including the guest stars would muddy the waters quite a bit.
Deceased Cast Members as of June 2017 (all male to date):
May 22, 2004: Richard Biggs (Stephen Franklin) – main seasons 1-5.
February 13, 2006: Andreas Katsulas (G’Kar) – main seasons 1-5.
May 27, 2011: Jeff Conaway (Zack Allan) – guest season 2, main seasons 3-5.
September 28, 2012: Michael O’Hare (Jeffrey Sinclair) – main season 1, guest seasons 2-3.
July 17, 2016: Jerry Doyle (Michael Garibaldi) – main seasons 1-5.
June 16, 2017: Stephen Furst (Vir Cotto) – main seasons 1-5. This death was the tipping point where deaths exceeded 50% for male main cast and for main cast who were in all five seasons .
Still Living as of June 2017 (male):
Bruce Boxleitner (John Sheridan) – main seasons 2-4.
Bill Mumy (Lennier) – main seasons 1-5.
Robert Rusler (Warren Keffler) – main season 2.
Peter Jurassik (Londo Mollari) – main seasons 1-5.
Still Living as of June 2017 (female; all still alive):
Claudia Christian (Susan Ivanova) – main seasons 1-4, guest season 5 (while in the main credits for the series finale, the cast listed was that of season 4; it was filmed for that season in case it didn't get renewed. She wasn't in any new season 5 material so best to split the difference and call her a guest).
Mia Furlan (Delenn) – main seasons 1-5.
Andrea Thompson (Talia Winters) – main seasons 1-2.
Tracy Scoggins (Elizabeth Lochley) – main season 5.
Caitlin Brown (Na’Toth) – main season 1, guest season 5.
May Kay Adams (Na’Toth) – main season 2.
Patricia Tallman (Lyta Alexander) – guest seasons 2-3, main seasons 4-5.