So I really wish they'd flesh out some better lore for Shaco as there seems to be a bit of a disconnect with the Champion Page and his biography.
_"Crafted long ago as a plaything for a lonely prince, the enchanted marionette Shaco now delights in murder and mayhem. Corrupted by dark magic and the loss of his beloved charge, the once-kind puppet finds pleasure only in the misery of the poor souls he torments. He uses toys and simple tricks to deadly effect, finding the results of his bloody “games” hilarious—and for those who hear a dark chuckle in the dead of night, the Demon Jester may have marked them as his next plaything."_
Whereas the Biography reads as, _"No one fully agrees from whence he came, and Shaco never offers any details on his own. A popular belief is that Shaco is not of Runeterra - that he is a thing from a dark and twisted world. Still others believe that he is the demonic manifestation of humanity's dark urges and therefore cannot be reasoned with."_
So while one section states that he IS in an enchanted marionette, the other states that he's some mysterious demon / manifestation and they have no idea where he came from.