I searched for this and did not find it on the message boards. And yes, I typed in the names of both NiGHTS games.
Anyways, NiGHTS. The nightmaren who has appeared in more sonic games than his/her own games. And no, he/she is not a Sonic The Hedgehog character, contrary to his/her video game appearances.
I've played NiGHTS into Dreams (haven't beat it yet) and I still have to play Journey of Dreams (Haven't played it despite owning it for close to a year now).