(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I Urzas Saga gains {T}: Add {C}.
II Urzas Saga gains {2}, {T}: Create a 0/0 colorless Construct artifact creature token with This creature gets +1/+1 for each artifact you control.’
III Search your library for an artifact card with mana cost {0} or {1}, put it onto the battlefield, then shuffle.