This answer is based on these clarifications made by @chasly-supportsMonica in the comments:
It is difficult to define evil. My requirement is that PCs do not
cause any kind of suffering to other PCs. They can murder, rape,
torture, bully, spew hatred, etc. but only NPCs will be affected.
Yes, toe-stepping that causes pain is not allowed.
With such harsh restrictions I can see only 2 solutions:
- the entire world comprises only 1 PC and it is a solipsistic universe (no NPCs);
- the world has only 1 PC and the rest are NPCs who are catering to all PC's needs and desires.
A solipsistic universe makes it impossible for anyone or anything to inflict suffering on PC, all harm is self-inflicted. This allows for free will and there are no innocent victims.
All-NPC but one PC world satisfies all stated requirements at any level of world complexity and technological development. Lower complexity and technologically undeveloped worlds where fully isolated regions can exist can have one PC per isolation zone.
These are the only solutions because even toe-stepping is not allowed. Thus, any communication with other PCs is potentially hurtful: Simple words or gestures can cause suffering in humans given the right conditions. The only way to fully protect PCs is to fully isolate them from all other PCs. Full isolation is not possible in a world with highly developed technology and complex interdependencies: Even the smallest decision of other PCs can have unintended harmful consequences for other PCs.
Unfortunately, there is a possibility that all-NPC but one PC world will not work out, especially if it has highly developed technologies. Industrial development, for example, leads to environmental contamination that harms all humans. I am not sure if this can be solved in any way. Even clean and sustainable technologies affect the environment and potentially can have a detrimental effect on humans. Perhaps, you can introduce magic that NPCs use to satisfy your PC.
I think that the question of God's benevolence is actually more interesting in the proposed scenario. Will God remain benevolent if all PC suffering is eliminated and PCs are given the freedom to murder, rape, torture, bully, spew hatred, etc.?
It seems that the PCs will end up being spoiled little brats as the best outcome. The creation of completely evil beings with no shred of humanity in them is a much more likely scenario, though. Can a god who breeds evil still be seen as benevolent?
If you are going to ask why evil beings are the most likely outcome, it is because it is not possible to know what pain is without ever experiencing pain. It is not possible to relate to the struggles of others if one never struggled before. If there are no consequences for bad behaviour there is no reason to stop. Moreover, NPCs will be reinforcing bad behaviour as they are prohibited from inflicting harm on PCs.
Additional thoughts and remarks (because comments are too limiting)
- Pain and suffering are not necessarily physical. Emotional pain and suffering can be much worse.
Failure to meet expectations, for example, may ruin one's life to a greater extent than a slow-progressing incurable disease. The pain of losing loved ones is greater than the pain of losing one's limbs.
To be frank, I am not sure if people can grow up and mature as persons if they do not experience any struggles in their lives. Can someone who has never experienced any setbacks and failures deal with the everchanging nature of the world or uncertainties it is full of? Can someone cherish something if they have never experienced losing something?
- What is a wrongdoing? What is good and evil? And, most importantly, who makes these determinations?
IMO, one of the implications of free will is that people themselves have the power of determination when it comes to good and evil. Moreover, moral definitions can change over time and differ across cultures.
Of course, some things are more or less clearcut: There is, probably, no culture in Earth history that would allow arbitrary murders of innocent bystanders. But most things are not that simple. For example, some cultures demand total obedience of children from early ages. A child of 2-3 years old is not allowed temper tantrums and prohibited from demanding anything. Other cultures do not say 'no' to children until they reach a certain age and parents comply with any demands of their offsprings to the best of their ability. Which of these approaches is wrong? Would not parents of both cultures accuse each other of wrongdoings toward children?
If God is the only one who has a say in matters of good and bad does it mean that people still have free will? Is free will limited to compliance with God's understanding of good and evil? It may be the case in your universe, but I am not sure if it is truly free will.
- Does inherently bad or inherently good exist?
I am not a supporter of the entire notion of 'inherently' anything. I think that our experiences matter more than our genes. There are people who are more prone to aggression due to their genetics, however, it does not mean that all of them will become unruly thugs. Aggression can be channelled in many different ways. It takes experience to learn them. The same goes for kindness and consideration. Even kind people can become criminals.
I would also say that it takes experience and knowledge of people to be truly kind and considerate. Otherwise, it is nothing more than politeness. Politeness does not require the ability to relate to others and their struggles, kindness does. Harsh words and actions can be manifestations of kindness when used in the correct situation. It is out of kindness and consideration a parent is strict with their child and punishes child's bad actions.
P.S. We probably have very different notions of morality (moral relativism makes the most sense to me), so take my words with a grain of salt.