If one or more counters would be placed on an artifact or creature you control, that many of those counters plus one are placed on that permanent instead
This cost is reduced by for each instant and sorcery card in your graveyard
But you don't need to go for the Thassa's Oracle MTG combo necessarily - usually it'll be enough to draw an enormous number of cards and play an enormous number of lands, putting you in a commanding lead
Then flip him to the 4/4 when our dork leaves and then our land dorks have vigilance and then you earthbend 2 each of our combats
After all, it doesnt feel too good to be the one to put the mechanic in a game only to watch your opponents reap the benefit
Sardelis confirmed that the enduring story condition works like the citys blessing: once triggered, youll keep it regardless of whether you lose artifacts, legendaries, or sagas (which all happen to be historic permanents, by the way)