Aside from being yuri-rific, the masks also fit in well with my favourite fan theory regarding these two.

This picture made me cry because of the blue and red oni masks, referring to the touching story of friendship and sacrifice.

The artist asserted that this is not a pun on “setsubun” and “seppun” (kiss).

Grahf said:
Aside from being yuri-rific, the masks also fit in well with my favourite fan theory regarding these two.

Namely that Asakura willingly took on the role of the antagonist so that Nagato could get closer to Kyon.

Brilliant! I had never considered that angle before. I like it.
Although it kind of doesn't fit given the events at the ending of "Disappearance."

Ralen said:

Although it kind of doesn't fit given the events at the ending of "Disappearance."