Otheym

Top of the rune stone:
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Otheym, pausing after touching the rune, waits to see if the room is going to collapse or a demon jumps out or they get teleported again. After a moment and nothing changes other than the blinking has stopped, he points to the rune next to the lit one
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You said two rows of four and the bottom left one was the one lit:
X X X X
(1 2 3 4)

L X X X
(5 6 7 8)
Otheym is gesturing at #6


and reaches until his hand hovers over it. He looks back at the two on top of the stone with him and says "You magic people. Yes?"