Toaru Majutsu no Index II: This Is It

Currently finished: Episode 21

After a short filler arc break (ep 17 and 18) that actually served as a lead-in to this final (I think) arc which has gotten very bloody very quickly, literally. They have gone on a big killing spree where people are just getting slaughtered left and right, and they're not afraid of showing blood. While at first glance it may seem that they have gone off to yet another offshoot again right before the season is going to end, as the arc progresses, it has become pretty clear that this may well be the arc that is the ultimately tie-in for everything in the story we've come to know so far. This, probably is the ultimate showdown we've all been waiting for since the beginning of the series. So if episode 17 and 18 somehow disappointed you. Don't be, because they aren't just some random offshoot filler arcs--they are actually the beginning of the end (I think).