Board Thread:Theories and Speculation/@comment-26381547-20150509000749/@comment-734582-20150512232204

Bambusek wrote: Well, they got a new powers from a pretty much god of ninjas, so while it was weak it wasn't that bad. What was much worse is Kakashi instantly mastering a full Susanoo only because Obito, that NEVER used this technique, "possessed" him.

Well since especially the Mangekyo gives this great ability to see through Jutsu, and Kakashi having seen the Susanoo being spammed, he could've used the Uber Analysis jutsu to figure it out. We don't really know what matures a susanoo (Apparently "anger") but it's possible that with Kakashi's darkness, he had enough for a mature one.

regarding the Tenseigan, i'd say it has some form of creation but it seems to be temporary. So i'm not really sure how it's supposed to work.