No... not the slasher. The phantom of the concert hall. He is none other than the great Lun.
I know the evidence is hardly overwhelming, but work with me here.
The Phantom is listed in the hero listing in RM2k, he has the same level scheme as other E6 characters (1-19). There is a weapon called "Lun Sword" that I don't believe is used. I believe that Lun wanted to make himself a playable character in the game but either he removed the ability to recruit the Phantom (HIMSELF!) or he's leaving it until beta ends.
That... and the Phantom knows way too much about dream estrana to be some asshole who got killed and had his aura absorbed.