There is no "Satan" or devil. Nobody ever needed any help to find their way to evil or selfishness. The Bible (the real translations, not the edits) doesnt even mention any fallen angels, or any other god of evil. that shit only appears in the hilariously named "New Testament", which contradicts itself, and the "Old Testament" every couple of pages. Only the Koran is as seriously screwed up and contradictory as the christian bible.
The primary flaw in all the "Abrahamic" religions is their reliance on dogma, commands and threats to force compliance with their rules. Do this, or go to hell, dont do that or go to hell... blah blah blah. Its all just commands based on the Appeal to Authority, which is a basic rhetorical fallacy. In Buddhism, the seeker is urged to do good works, and better himself, for the sole purpose of bettering himself, and thus the world around him. Zoroastrianism teaches that service to The Light and Truth (Ahura Mazda) is it's own reward, and the world will be a better place for your efforts.
Ancient Celtic faiths described the world around us as simply one reality among many, and sometimes people, forces and powers can cross from one to the others. Like a dish of soap bubbles where each bubble of reality connects with several others, which connect with others and so on endlessly, and the further you get from our reality, the more bizarre the new realities become. This is where their "Gods" (not gods in the eastern sense, more like people, or in some cases animals or even creatures with power) come from, including the creators of the reality we understand, Cernunnous (master of death rebirth and renewal) and his consort Arianrhod (mistress of creation crafts and labours). Both these "gods" came from someplace else, and after Arianrhod created the first examples of animals and people to fill their new world, Cernunnous gave them life, death and the ability to reproduce. After that, they simply watched and enjoyed the activities of their creations. This inclusive world view served the Celts for centuries, resulting in one of the most advanced and wide-spread cultures in the ancient world. Artifacts and ruins from Celt cultures can be found from the British Isles to the deserts of northern China and southern India, all without an empire. The Celts even taught the Romans and Greeks to use steel. Not too shabby for painted savages.
Step away from the dogma. There are many religions, faiths and belief structures in the world that dont rely on outward forces to compel goodness, or nefarious evil spirits to tempt us into evil, nor horrifying punishments for those who choose to act in ways that could be considered sinful. The dogmatic faiths are the ones that cause the world's troubles, While the rest of the world suffers, the popes priests mullahs and imams just get fat and rich.