» Sat May 28, 2011 7:33 pm
As far as I can interpret the in-game books, only a decendant of the "dragon blood" can wear the amulet. That doesn't mean a "close" relative, or the eldest offspring, it applies to ANY decendant. It also does NOT apply to other kings or emperors who are not direct decendants.
Given the amount of intermarriage between noble households, that would very quickly grow to include just about every noble in Tamriel, and a large number in other places over time. By the time in which the Oblivion crises takes place, you could probably take any beggar off the streets of the Imperial City and have at least a 25% chance of him/her being able to wear the amulet. Mankar Cameron is probably directly related to Tiber Septim in 16 different ways, although not even remotely in line for the throne. Having him wear the amulet is no big deal, in that respect.
I suspect that the only ways to determine whether or not someone could wear the amulet would either to do extensive geneological checks, or just try it. It doesn't say whether failing would be fatal, or whether it just wouldn't allow itself to be worn, so we have no basis to know whether or not they could have just gone around "testing" candidates at random. If it were fatal for anyone not of the "dragon blood", that would make it a calculated risk for any potential "Emperor wanna-be", a final "do-or-die" rite of passage before being allowed to assume the throne. Your character either couldn't or wouldn't wear it, and the last game didn't allow you to take that "test", so we may never know.
The situation during the reign of Potentate Versidue Shai'i remains unexplained, because he was certainly NOT a decendant of Allesia (although he might have his own "dragon blood" in a cryptic sort of way). The Oblivion gates could have appeared at any time during that interval, with nothing to prevent it.