Reaper is by far the weakest of the NK classes and the most difficult to win as by a longshot. The abilitiy to silence a player and stop his vote means that reaper can win in a 3v1 generally and a 2v1 always, but that's IT. That's absolutely all you have as reaper. It is a ludcriously weak class in all other regards, and directly, massively worse than the other two.

As posessor I win more than half the time, because good jumping can really screw with BD and make it impossible for them to pin you down as the evil - especially if you're leaving behind well-placed bodies. Posessor, in my opinion, is above and beyond the easiest NK for a skilled player, because you can strongly control the game with good deception. Additionally, you have complete immunity to being killed at night by conventional means.

As sorcerer I don't win too often because Sorc, like the reaper, is stuck in one body as a 'killer' class, which makes them extremely vulnerable to princess, maid, observer, alch truth potion - even the damn MM investigate ability coming up as unconvertable can out you to somebody. But the fact that the Sorc effectively gets TWO kills a night with walking bomb and magic missile and can do a mass kill later means that a well-played Sorc will have everyone walking bombed by day five or six, which leads to a win if you've played your cards right. You also have complete immunity to being killed at night by conventional means.

So, with that in mind, let's look at Reaper. They share the disadvantage of being very easily outed by a large number of classes and being unable to move bodies like the sorcerer. They are only able to kill one person a night, and having that person only die on the next night is at best irrelevant and at worst an actual DETRIMENT. Even braindead BD will soon realize that someone is not talking if you're killing important classes and figure out it's a reaper game, and I can count the times even the stupidest of BD have been convinced to lynch a reaped target on one hand. Reaper has the abilities to silence a target and stop them from voting for one day - at the cost of two souls, which means you can do it, at most, twice. Their attack can be empowered to ignore night immunities, too - at the cost of two souls, which makes it only useful if there's an outed prince or when you really need to get an endgame edge. Since you start with two souls and will, if you kill every night, have only four more by night five, you've effectively got a maximum of three uses in any combination of these abilities (and a mimum of one), compared to the Posessor's, for instance, three jumps. So, what does the reaper get in exchange?

Well, his attacks can be followed by observer, unlike any other NK, and his conventional death immunity is conditional and costs a soul.

Like, come on. From a purely objective standpoint, the Reaper is just objectively and considerably weaker than the other two NKs. He has very little control over the flow of discourse like the Posessor does, half the killing power of the Sorcerer, conditional immunity, and even more classes that can discover him. It's just insane.