it allows chaining animation and skills to create your own custom class.
here is mine:
https://www.youtube.com/watch?v=QmG4nV6yGyk
here is some other people's creation:
https://www.youtube.com/watch?v=o03TIpOpias&t=70s
http://i.imgtc.com/iJyp6bF.png http://i.imgtc.com/ZBw36Qh.png
Thanks for the peeps that made the pics <3 if i make typos it means i am on phone