That's not even in doubt, is it?Actually, I wouldn't call this filler - it seems to suggest even more strongly towards are little friend in the darkness teleporting the two of them out. Maybe that's why it's sleeping - it's drained from spell casting?
This is stuff all we needed to know (where everyone is, who knows what about which), so it's not strictly unnecessary the way filler would be. But it is sort of cramming as much information into one strip as possible in order to get it out of the way.
If anything, I would say it's the equal and opposite of filler: it's bookkeeping. Tally up where everyone stands so we can end the arc and start a new adventure.
I seems much more like an Epilogue for this plot arc. Finishing Roy's resurrection and the OotS standing together again will probably be the end.