Well, it's more of a question if there was two phantom slashers.
Many people think that Rhue's sword is an Illumati/Swadow Sword (please don't correct me on my spelling, I'm a n00b, it's okay) and this seems to be a reflection of his personality (he cares about people like Lexus deep down, but killed Lyrra, however he did feel much remourse).
Now when the PS pulled the Rhue's sword out of Slade (it was "growing" into him or something) who's to say that it wasn't going to kill him, and by pulling out that sword he did Slade a favour and returned it to Rhue.
At times the sword itself can be evil (eg. killing Lyrra) or good (eg. making Rhue hit the Shadow Sword), but for any reasons in my personal opinion I reckon that there are 2 phantom slashers.
Also, here's a ridiculous theory, but who's to say that the Paradans wouldn't be a prefect cover for a manipulitive, evil organisation, who would suspect THEM, also, myabe the shadow demon/man that Rhue fought in the pits was simply just a demon, not everything int he plot has to have significance ya know?
Well that's just one n00b's opinion.

