What is happening in the "Depth of Field" specials?


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?

![Look at the pretty glyphs!](https://i.stack.imgur.com/hdDmZ.jpg)




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.

![Rikka and Dekomori sit in the clubroom, wearing cardboard
boxes](https://i.stack.imgur.com/iTTIY.jpg)

The preceding episodes of Depth of Field depict the way they imagine their
role-play fight to take place.




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.

![Rikka and Dekomori sit in the clubroom, wearing cardboard
boxes](https://i.stack.imgur.com/iTTIY.jpg)

The preceding episodes of Depth of Field depict the way they imagine their
role-play fight to take place.

