How do I create sprites and animate ?

Okay so ... I recently joined unity community. I have been trying to create an side scroller action-rpg for android with 2 graphics which are not pixelated but in vector. I have been really inspired by " Reaper - Tale of a Pale Swordsman " and want to make character and object animations along with art style similar to it. From the looks of it, it seems as if each part of the character's body is divided into an object that moves in the animation without having to create repeated images. The hands are not connected to body but hover around it while the weapon is attached to the hands. How can i do animations like that ? It will a lot easier for me create a single image in vector and move it for different actions rather than creating multiple ones and the art style i want won't fit in with pixel graphics. Also i will include around 5 characters with different class , weapon, skills and a cool feature called " special skill " which will be like special moves with different sprite and will cause a certain time-pause where everything except target and character stops while the move takes place and damage is dealt. Can anyone help me ?