Upon entering the cave Father Fujimoto and Mephisto found only one son of Satan. They question what happened to the other, but they move on ignoring it. Mephisto formed a bet for the young Yukio's life. Unknowing to the Order, Rin was snatched away to Gehenna before the exorcists came. Will the twins meet? Will they laugh, or will it be on the bloody battlefield for fate of Assiah?