You know I was just thinking and I think I figured out this Nightmare guys plan.

Get a character and build him up using the auto train system.
Once he gets to a certain amount of levels in training you stack him with cash regularly and let everyone beat the piss out of him which causes the character to lose level points.
this takes a while but once the character is down to level 1 he still has the stats of a level 15 who has done nothing but trained himself there.
then you do the auto train again up to a certain level and you have this hulk of a sleeper at level 5 kicking level 60 players asses all day long.

pretty kick ass deal if you ask me.