He might notice his attacks don't seem to be as effective against the dragon, but it's hard to tell.
Everyone can notice if they beat the disguise check with perception. However, you should know that simulacrum has a 12 hour casting time. So it's not something that could be cast mid-battle. This is not a viable tactic. He would have to already have a simulacrum made, and then at that point that battle isn't against one red dragon and a simulacrum, it's effectively a red dragon and another red dragon with half HD and abilities (effectively half CR).
Why wouldn't his attacks be as effective against the dragon? The simulacrum is an evil dragon, just like the original.
The best way to tell if it's a simulacrum is to kill it and wait for it to melt.
Why wouldn't his attacks be as effective against the dragon? The simulacrum is an evil dragon, just like the original.
The best way to tell if it's a simulacrum is to kill it and wait for it to melt.
Because the simulacrum is not the target of the smite evil.
Of course, as mentioned the 12 hour casting time makes the point somewhat moot.. unless there is a magic item involved that somehow would get around that restriction.. or maybe a contingency? I haven't given that a full read so I don't actually know if it is viable.EDIT: It is not. Just checked and simulacrum is too high a level.
Ah, a preexisting smite against the original dragon. Also, having rarely played a paladin, I forgot that the smite lasts all day instead of just for the duration of combat like similar abilities. Sorry about that.