Evangelion universe is complex. For this reason, Evangelion rebuilds should be regarded as complementary to the anime series. It's advised to watch them after the series in order to have a better understanding of the deepest topics explored in Neon Genesis Evangelion. According to some anime fans (i.e. the Loop Theory of Neon Genesis Evangelion) the original series and the rebuilds are someway connected in a timeline which is not linear but repeats over and over with only small differences each time. Evangelion rebuilds titles' also refer to this concept of time 'You cannot Redo' and 'You cannot advance'.