Watts family
When "EastEnders" began in 1985, the soap focused primarily around the affairs of three families: the Beales, Fowlers, and Watts. However, much of the show's early success stemmed from the drama surrounding the Watts, especially the antics of Den, who as owners of the Queen Vic pub (the show's most prominent set) were usually in the limelight. This prominence, at a time when "EastEnders" was at its most prolific in terms of both the media and audience, meant the Watts became perhaps "EastEnders" most eminent family and the characters known even to those who did not watch the show. Such was their success that producers went ahead with an experimental episode format centring on just Den and Angie, during which Angie lied about having cancer; so successful was the airing that it has since been repeated, and the format expanded to include "three" and "four-handers" (between 3 and 4 characters). Such episodes are highly prestigious and feature only the most popular and prominent characters in the show; thus, all the Watts, aside from Vicki, have featured in such episodes.
John Altman (actor)
In 1985, he first appeared as Nick Cotton in the new BBC television soap opera "EastEnders", appearing in the very first episode in February that year. He went onto make recurring appearances in the show and has been part of many famous storylines in the show including the murders of Reg Cox (whose body was found in the very first episode) and Eddie Royle, his attempt to kill his own mother Dot by poisoning her and his various feuds with characters like Pete Beale, Den Watts and Mark Fowler. 
His character was also given his own television spin-off episode titled "Return of Nick Cotton" which aired in October 2000. His character was killed off in the episode that aired on 13 February 2015 and made his final appearance as a corpse in the episode that marked the 30th anniversary of the show on 19 February 2015. His body was found in the same way as his victim Reg Cox was found in the very first episode. A year earlier, his character's death had been announced in the show, only for it to emerge within a few months that Nick had faked his own death.