The death leaves Mr. Fantastic, Invisible Woman and the Thing.
Death is not uncommon in comic books. DC killed Superman in the 1990s, only to bring him back. At Marvel, Captain America was assassinated on the steps of a court house and returned, while Marvel's mutant band of X-Men know death so well that the Grim Reaper is on speed dial - Thunderbird, Phoenix, Nightcrawler and others have been felled.
The Associated Press contributed to this report.