This is very interesting, because the prophecy said that Denji would be the one to kill both Aki and Power, which means one of several things: either Aki's attempts to remove them from the Division made enough of a change to make Denji not be the one to kill Power, Denji opening the door for Makima qualifies as "killing Power", or Power isn't actually dead. I'm hoping its the third one, but I'm assuming it will be the second.