Teen Wolf AU where the reason the Dread Doctors wanted Theo and Tara is because they hold two extinct supernatural breeds but the DNA is dormant because their linage are so outta wack that it’s hard to awaken.
Except Theo awakens his Black Dog dna first and out of no where while he and Tara went on a walk in the Preserve, The Black Dog in him was slightly tainted due to the Dread Doctors experiments and made him more susceptible to becoming evil. Hence, he goes into a trance and accidentally murders Tara. He doesn’t remember at first but it suddenly dawns on him and he doesn’t recover from the trauma. Theo doesn’t tell any of the Doctors and the Doctors don’t find out bc it goes dormant again.
UNTIL Theo comes back from Hell. The Ghost Riders bring back Black Dog and then the whole war brings his primal, Direwolf out and so bada bing bada boom, Theo is a perfect chimera not bc of the dread doctors but because of his Direwolf + Black Dog dna he had inherited; bonus: one eye is alpha red and the other is pure white.
He probably has control problems after the whole hell situation and decides to leave Beacon Hills for a while until he has himself under wraps. Comes back for back up or sm and finally tells the Pack what he really is and stuff
I don’t know, just a thought :)