Introduced in 2004 as Gabriel and Sarah, the alleged twin children of Norman Osborn and Gwen Stacy, with Gabriel becoming the Gray Goblin and later the second American Son, their true origin is later revealed during the Sinister War story-arc as a series of constantly dying and recreated clones of Peter Parker (with a combination of Norman Osborn's genes) and Gwen, created by a corrupted A.I.

[1] The story arc "Sins Past" by J. Michael Straczynski reveals that Gwen Stacy fell pregnant with twins after having sex with Norman Osborn, a boy and a girl to whom were given birth while in France.

During a brief confrontation with Sarah just after the DNA analysis completed, Spider-Man learns that she clearly resembles her mother, but is forced to escape when Gabriel attacks.

[7] A follow-up story titled "Sins Remembered" was written by Samm Barnes with art by Scot Eaton.

Straczynski ultimately wished to retcon the characters out of existence using the events of the "One More Day" story arc, but was not permitted to do so.

[15] Gabriel hears a planned ambush by a police squad and proceeds to attack; before he can do any real damage, however, he is stopped by Spider-Man.

Planning to redeem the Osborn name, Norman states to Kindred that he will find the truth that he talked about.

[24] Carlie Cooper is asked to investigate the corpses dug up by Kindred, and is particularly horrified on uncovering an extra one.

He starts by helping Sandman solve his immortality problem and uses a special machine to resurrect Electro.

[26] As Kindred gets more serum from Chameleon, Doctor Octopus and Electro recruit Kraven the Hunter in exchange for his help in hunting Lizard.

[27] Carlie learns from Harry that he was lured to Europe by Kindred after following a trail of transactions from several dormant Oscorp bank accounts.

Arriving at one of his father's former real estate holdings (which bears a resemblance to the building that raised Sarah and Gabriel Stacy), Lyman was attacked and captured by Kindred.

After Doctor Octopus coerces Curt Connors in using the Isotope Genome Accelerator on himself in order to separate his Lizard side, Kindred plans to add Mysterio to the Sinister Six.

Harry tells her this is not the first time he has failed them, and that no matter how happy he is, how hard he tries to put things right, something is always there to remind him that none of it is real, and that none of it will ever last.

After more coaxing from Carlie, Harry suddenly notices that the door to their cell is open and suggests there is a way to escape.

Sarah and Gabriel were part of a major cloning conspiracy orchestrated by him, Mysterio, Mendell Stromm, and The Chameleon.

Sarah's condition was stabilized through a blood transfusion from Spider-Man, leaving her significantly more mentally stable (although her precise strength level is unclear).

As Kindred, the twins were bestowed by Mephisto with the demonically enhanced capabilities of immortality, super-strength, and control over the centipedes like the ones that can protrude out of them.

During the "2015 Secret Wars" event, a vampiric Gray Goblin can be seen chasing Blade and Howard the Duck in the Battleworld domain of New Quack City.

[37] J. Michael Straczynski later stated originally wanting Peter Parker to be the father of Gwen Stacy's twins but the editors vetoed the idea, feeling that having two adult children would age the protagonist too much.

of Norman's son Harry, serving as the true dual identity of Kindred, partly due to the huge backlash the original storyline caused among the fans, angered by the distortion of Gwen Stacy's character after the revelation of her supposed sexual intercourse with a creepy and evil man like Norman Osborn.