How do you unlock sparda devil triger in Devil May Cry

This answer is for devil may cry 3.

First you have to beat dante's story on normal mode.(to unlock normal mode beat easy.or Just start the game on normal.) The new clothes you will get should be dante with sparda's sword over his back. Then do any mission with rebeillion weapon in your weapon set, then switch to rebellion then do devil trigger. Instead of changing into dante's demon you will turn into sparda. Hope this helped.