Hello everyone and welcome to my discussion on the Nemesis Samael and his 3 different forms.
General Overview: Along with Uriel and Kassia, Samael is the only monster capable of reviving allies, which is an unbelievable asset in any War to save War Coins. Also, he possesses the ability to give an ally an extra turn, which is what gave Demise such popularity, plus he has the Bulwark trait instead of a Nemesis trait, which is a huge boon to block any kind of status effect. No matter what the form, Samael has exceptional Speed and Life, which fits his potential rule as a support perfectly. Along with his high Base Strength and the ability to use his extra turn move on himself, Samael also makes for an amazing attacker.
Comparison between Fever Scatterer and Plague Carrier: This choice depends mostly on whether you focus on one-shotting or outspeeding deniers. Fever Scatterer's Speed is already higher than most deniers, but Plague Carrier ties with the likes of Baba Yaga, which allows him to outspeed almost any denier. However, neither can outspeed Krampus or Jasastur, the prime Dark deniers, so the difference between the two forms' Speeds has reduced importance. Furthermore, Fever Scatterer's Light attacks will greatly damage Dark monsters even without Strength runes, plus they apply the valuable Sunburn-one applies Blind with it too, and his Double Damage+extra turn will allow an attacker to one-shot the enemy team. Plague Carrier, on the other hand, has higher Speed than a vast majority of deniers, and his extra turn move instead gives Precision+Damage Boost, with 100% Stamina restored instead of 50%.
Conclusion: My personal preference is Fever Scatterer thanks to his greater Strength and way higher damage against Dark monsters, and most deniers having at most 3465 Speed. Though, Plague Carrier is a very plausible choice to make your "attacker faster". As an attacker, Fever Scatterer is the superior choice, and I believe he is a better tank too thanks to his accuracy reductions.
MASSIVE EDIT: I didn't notice this the first time, but Plague Carrier's extra turn attack has 0 Stamina cost. If this isn't a bug and holds true, Plague Carrier is the obvious choice for a support since he devastates General Thetys and any other Stamina drain that may come your way. Fever Scatterer would still have merit as an attacker, but Plague Carrier would still give him a run for his money in that aspect due to being immune to Stamina drain.