Question on Shadows Main Story and playing with Yasuke (Mild Spoilers)

Based on the trophies I saw the main story is divided in Prologue, three Acts and an Epilogue.

I finished the Prologue and I’m currently doing some quests with Naoe, more precisely I created the forge in the hideout and now I’m tracking down the first figure from the league of Shadows.

When do I get to play as Yasuke? Is it okay to go for the bad guys and see how the story flows? Or did I missed something and that’s why I can’t play yet with Yasuke?