These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Jashin was one when he was alive. He was a cruel and merciless Warlord who killed any who stood in his path, butchering entire countries and people years ago before the main timeline. He even used his own son as a Sacrifice to create a Summon which requires a hundred Sacrifices each use. He had no Freudian Excuse like others, he simply killed because he could. Eventually The Sage of Six Paths confronted and killed him but it got worse as his remaining followers deified him and vowed to continued killing all in his name.
And in the Present time line Worshiphers Hidan and Keiji Sosano are just as bad. Hidan betrays Akatsuki and murders dozens of ninja and people and nearly kills Kakuzu and attacks Konoha with followers. Keiji takes over Earth and proclaims that they will start a Fourth Ninja War and that they proclaim an Age Of Jashin where all will worship him or be killed. Hidan even tried to go back in time and kill Naruto and change the past when he was born and see to it that Kyuubi destroys Konoha and would've if Orochimaru hadn't stopped him from doing so. Keiji willingly sacrificed thousands of troops in battles and killed the woman who loved him just so his plans wouldn't go unnoticed and be able to put put his final plan into action.
Fridge Horror: Keiji Sosano was revealed to have been a child who was taken by Hidan after Hidan destroyed his village and killed his family and taught him the ways of Jashin. Considering how Hidan is, who knows what kind of life he lead growing up under him.
The Jashinists do this when they attack and destroy a temple killing numerous monks including children, why? Cause Keiji saw their pacifist ways an insult and ordered their destruction That makes them go from your average evil army into a psychotic butchers who seek to destroy all that oppose them.
They done it again in a flashback as it's revealed that before the Final Battle they had destroyed a village and piled the bodies of men, women, and children, ontop of each other
Danzo does this when he he receives orders to send supplies and goes to do so but instead opts not too. This leads to a crushing defeat due to lack of supplies with several dying.
Nightmare Fuel: The reveal that Keiji and his Team in the Forest of Death crucify Oboro and his team onto trees and they are still alive.
Ron the Death Eater: Averted, most of the people in Konoha are the same as they are in Canon aside from being unsure if they are able to trust Sound. Compared to other stories where they are all turned evil at once