believe anything you want and do anything you want.
You are free to do so.
Yes 'freedom of believing' or 'freedom of opinion/attitude' is a 'universal right' for every 'individuated unit of consciousness', with certain limitation of course, bounded by universal law in this universe.
By 'universal law' I truly mean 'universal law', the law that exist even before human exist and continue to exist even after human species has become extinct. (and also the sun, the earth planet become extinct)
However moral laws and a system exist from the creator and judge of His system. This system has only two paths and leads to two outcomes.
1- Follow GODs system and accept/follow/abide by His laws. Success and a new happy experience/life will follow after here.
2- Do not accept/follow other systems/your own way/rebel against the laws of the creator. Failure and a new miserable experience-Worse than this one we are experiencing- will follow after here.
Let's dissect this one by one.
1. Universal laws a.k.a "Creator's laws" is universally and automatically binding.
Nobody, including non-human entities can break it. No angels / demons / deities / alien can break it.
So there's no option of "not following" or "not accepting".
2. Thus it implies "rebellion" from universal laws is an impossibility. No entities can break it, not even Devil/Satan/Lucifer or whomever. The notion of "entity" rebelling to "One Infinite Creator's law" is quite ridiculous, using LOTR metaphor above, it's similar to Sauron rebelling to Tolkien or Mickey Mouse rebelling to Walt Disney which is of course an impossibility and quite ridiculous.
3. Among the universal law is the 'law of opposing pair' which I've highlighted above, light x darkness, love x hatred, humility x pride, forgiveness x vengeance, security x fear, every 'thing' has it's own opposition pair. Personified; Angel represent the former while Demon represent the later as it opposite. Both polarity exist and both are still within the governance of this universal law. No creator's law is being broken here.
4. There's also another law, which functioned like a 'mirror', what goes around comes around, some people call it the law of 'karma'. Again this law also cannot be broken. You might refer to this law when you're refering to #1 above. Spread love and you will be loved, forgive and you will be forgiven, spread happiness and you will be happy. And the opposite is also true, referring to the 'law of opposing pair', spread 'not love' and you will not be 'loved', spread hatred/fear and you will experience fear/hatred etc...
This law is not a form of 'punishment' as it functioned exactly like a mirror, it's a form of 'learning'. As one have experienced both hatred and love, one will naturally and eventually choose love. And this applies to everyone, human or non-human. Demon/Satan or any entities lenient towards spreading hatred and fear will always experienced hatred and fear themselves, until they 'jump/switch to the opposite', again the law functioned like a mirror and it's applicable to all form of entities, not only human.
The above is the answer of the 'right system' that you asked before and again it's automatically binding. If all universal laws was to be summarized in one ultimate law, it's the "Law Of Love".
As ultimately all will be forgiven when they start to forgive themselves.
And forgiveness is an expression of the highest form of love called 'unconditional love'.
That's the reason why I often said, if you want to be forgiven then forgive others, if you don't want to be judged don't judge others, if you want to be loved then love others. Because the law functioned exactly like a mirror.
Well not only me, actually Jesus, Siddhartha, Lao Tse and many other people also stated the same thing using their own style and languages. Again this law is universally binding, thus not only applicable to 'human', it exist even before human exist and it shall continue to exist even after human become extinct.
That's among the reason why I also often said Jesus, Siddhartha, Lao Tse recommend the 'attitude of islam' but of course it is NOT "The Religion of Islam".