Board Thread:Questions and Answers/@comment-173.238.72.40-20150331214350/@comment-25047329-20150331223445

Partly it's because somethings are really different and partly it's because somethings are outright ommited. The anime over all was just not that faithfull an adaptation so things like character development, plot points, backstories, and even entire arcs were left out. Due to that there isn't a real jump off point from the anime to the manga. The events that happen in :re heavily depend on what happened in the manga and since the anime either didn't show or properly explain some stuff, trying to jump straight into it would just be really confusing.

The best option really is to just start from the beginning.