(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)

I, III - Choose target creature. Its owner shuffles it into their library, then investigates. (They create a Clue token.)

II, IV - Create a 2/2 black Alien Angel artifact creature token with first strike, vigilance, and "Whenever an opponent casts a creature spell, this permanent isn't a creature until end of turn."