I actually haven't done this but me and my mate were joking about the idea of our ESO characters being ancestors to our Skyrim characters as the Skyrim events are something like a 1000 years after the ESO events.
3 of my toons, before I name/race changed one of them, were all former soldiers in the Imperial Legion before the Three Banners War. One of them defected to the Pact, the other two to the Dominion because they felt the Queen better aligned with their personal goals and beliefs. All three of them were in a love triangle (one girl, two guys)
Those who do it levelling loads of characters, don’t you get sick of doing the same bits over and over?