There's a thing on PWI-PWCN called "Celestial infants" you pick a "spirit child" and you rise "lvl" it higher lvl unlock some unique skills.Not sure if its from one but at some point you gonna get a new thing on your game UI and with a hotkey connected to your Celestial Infant,once you use the hotkey you will turn into that Celestial Infant you choose.
This trailer is probably a new expansion that you get in just by using your Celestial Infant.
