The Depth of Field specials (included with the BD/DVDs) depict Dekomori and Rika going at it against each other in giant, magically-powered CG mechs. What's the story behind this?
Are they roleplaying (while playing some game?) something or is this set in an alternate universe?
In Depth of Field: Phase 6, it is revealed that Rikka and Dekomori are engaged in some sort of role-play thing in the clubroom. They seem to be pretending that the cardboard boxes they wear are mechas.
The preceding episodes of Depth of Field depict the way they imagine their role-play fight to take place.
