New character - Gin
Gin is a Water Warrior, just like Charlotte. If you've progressed through Dimension 5 and 6, you actually met him there - for sure his annoying First Strike passive that allows him to attack anyone first gave you trouble then and now you will be able to use it too!
You can see him in action in this video.
New character - Marguerite
Marguerite is a Light Mage who is more of a Mage/Priest hybrid. She can both heal her allies and deal massive damage to enemies - her specialty lies in stealing buffs and increasing her own damage based on the number of buffs on her.
You can see her in action in this video.