Hello everybody!
I'm new in this community, and I'm not a native english speaker, so I hope you'd plese me if my english is not the best.
I've been a spider-fan for a very long time, and now I'm being obsessed with the question of Kindred's identity. I've read your theories, some of those are very intresting. Now, I'd like to show you mine.
I've being thinking about it, considering charachters like Spidercide, Traveller and even Ken Ellis, but now I'm convinced I've just found a very probable candidate: Arthur Stacy.
Think about it, by checking also few facts:
1) He was the head of security of the Oscorp a long time ago, so he knows well both Norman Osborn and Mendel Stromm, and of course the rivalry between them.
At that time, he was both obsessed and terrified by Norman.
2) He could have the same age of Norman, more or less, so he could be referring to Peter, Gwen, Harry, Flash and MJ as "children", by knowing also them and their history with Norman.
3) Kindred told Stromm that he knows how does it feel to live in the shadow of another man. In fact, Arthur was used to it, back then: he spent his professional life in the shadow of his brother, George Stacy.
4) As a former policeman and SHIELD agent, he could have a lot of information about everyone, from criminals to common people. He could also have being tightening ties with several criminals and vigilantes, just like Fisk, Mysterio and the Black Cat, in order to track them down later and even blackmail them.
5) Arthur had issues with Kingpin. This latter tried even to kill him, back at the times of the Sen. Ward Saga. Through Fisk, he could also have something to do with Felicia.
6) After the first death of Ben Reilly, he came back to NY in order to persecute both Peter and Spidey, since he thought them had something to do with the deaths of his brother and his niece. Then, he changed his mind, became protective a lot to Peter and his relatives, and made himself a precious allied for Spider-Man. Kindred interest in protecting MJ could be referring also to that period. At that time, furthermore, , he could have discovered that Peter is Spidey, thanks to his dectetive-skills. During this period, he developed also a sense of "affinity" (kindship) with both Peter and Spider-Man.
7) Back in the days when Peter and Gwen were a couple, he could have been even considering himself as a sort of "kinfolk" for Peter. Here are both the meaning of the term "Kindred".
8) When Arthur and Peter became very close, he referred to him sometimes as "Pete".
9) The only problem left is his possible death and the time he could have being spending in Hell, but it could also be easily reconnetted. Again, back to the Ward story-arc, during the Maximum Security crossover, when the final showdown between Ward, Stacy and Spider-Man took place, Ward tried to infect Arthur with the Z'nox Virus. He could have really infected him. Then, Arthur could have died because of this and, due to something wrong he could have done as a SHIELD agent, he could also have gone to Hell, where Mephisto could have approched him by telling him the truth behind the death of his niece Gwen: that Peter/Spidey himself caused her neck to be broken when he tried to save her by grasping her with the web. THIS could be the "TRUTH of what Peter has done" to which Kindred refers. In order to persecute Peter, Mephisto could basically have done it by making Arthur his agent, and then Arthur could have been reaching out for Quentin Beck in Hell, just to make him his instrument against Peter. Now that Peter and MJ are back together, Mephisto can try to prevent they to be married again. Kindred hires so Mysterio in order to "deny them" what they want, a life together as a married couple. By accomplishing this goal, Mephisto's will would easily meet Kindred's/Arthur's will to prevent Peter/Spidey to cause MJ's possible death, and so to protect her.
Finally, I add only that, in my opinion, Kindred, whoever he is, is actually not interested in killing Peter, but just in making him recognize what he did (maybe to Gwen), and in making him so suffer for it.
I know that this theory sounds pretty weird, but makes a lot of sense for me.
Tell me what you think about it, plz.