Just… Watch, and smack your face for not thinking of this in your AU.
J@(K is the final boss in the U:R CH2 genoc1de route. After you k1ll asgore, you walk into the barrier to free chara. But the barrier is no longer there… there is a long dark hallway, but after you get to the end, the door disappears. You must go back. It disappears again. (This continues in a loop of 5) after you go through the door, you see a shadow. The room looks oddly like the judgement hall, but with the garden in the middle, and lights. The curtains are covering the windows. Then a fight starts between you and this guy, with about 99999 phases (not really). VERY hard.
