Janus Stark debuted in Smash! on March 15th, 1969.
Born in 1840 with bizarrely rubbery bones allowing him to contort himself in ways no normal person could, orphan Jonas Clarke escaped the brutal regime of Simon Tragg's orphanage and grew up on the streets, where he befriended the beggar Blind Largo, who taught him pickpocketing and lockpicking. As an adult Clarke reinvented himself as the escapologist and showman Janus Stark, and became something of an amateur detective. He died in 1880, at the age of 40. Unusual physiology proved to run in the family, as Janus' brother's modern day descendent John Stark possessed superhuman strength and was visited by Janus' ghost.
Stark enjoyed a four year run in British titles Smash! and then Valiant, and was reprinted in France by Mon Journal in his own title, Janus Stark, whose pages also reprinted other British strips including Adam Eterno and Zarga. from 1973 to 1989. When the French title ran out of reprint material, it produced new stories of the adventurer, finally killing him off in #89 in May 1986. A plaque at his grave, visited by his brother's descendents in that issue, identified his year of birth and death. The French comic continued for another three years reprinting older stories; the Janus Stark stories stopped with issue #125 in June 1989, but the comic continued for another ten issues before cancelling, still titled Janus Stark despite the character no longer appearing within.