Hello everyone and welcome to my discussion on the Nemesis Samael and his 3 different forms.
General Overview: Samael is a supremely powerful support that can also function as an attacker if he wants to. He has an incredibly wide arsenal featuring buff/debuff removals, revivals, heals, a turn transfer, 0 Stamina attacks, Tortures and high Base Powered attacks. On top of this, Samael's trait is Bulwark, making him fare very well against debuffs. Disease Spreader is hopelessly outclassed by the other two, so forget about getting him.
Comparison between Fever Scatterer and Plague Carrier: Fever Scatterer's turn transfer move gives its target Double Damage and 50% Stamina. He has more Base Strength but less Base Speed, and has Sunburn as his choice of Torture. Plague Carrier's turn transfer move gives its target Damage Boost, Precision and 100% Stamina, and it notably costs 0 Stamina itself. He has more Base Speed than Fever Scatterer, but less Strength. His choice of Torture is Bleeding.
Conclusion: Plague Carrier always wins here because his turn transfer move costs 0 Stamina, which still remains as one of the most broken moves in the entire game - plus, the Precision goes a long way in making sure that the target hits the enemies. Still, Fever Scatterer is very strong in his own right, so don't be sad if you end up with him instead somehow.