Soma

History
An eccentric college friend of Tetsuo's whose expression virtually never changes, Souma specializes in hyperspace theory, and is the one to suggest that Machi's neck is actually in another dimension, acting as a wormhole between her head and body.

Tetsuo calls him in when his niece reports being haunted by a demi. Unlile Tetsuo, who thought she was simply messing with them, Souma reminded his old friend about perception; they only see her, due to the demi's ability making them observe another dimension from the one haunted.