Angel worlds are one of the biggest advantages and bastions of power that the Federation and the alliance has under their control. There are 16 of these scattered across the Universe with 5 being located in the milky way galaxy. These are worlds where heaven energy is so high that except the strongest ones Demons cannot exist there without any outside support. If any demon does manage to exist on that world then it will find itself in a completely hostile and alien place with nowhere to run or hide. The wildlife of these planets are extremely hostile and aggressive to demons and will attack them on sight. They all also have the special divine blessing for being able to detect demonic energies and corruption, no matter how small it may be. Besides that angels are found a lot in these planets and guard the planet and its inhabitants from harm.
The planets themselves are sentient and have a world spirit possessing them that will do everything it can to impede any demonic threat to the planet. This includes causing natural disasters at places where demons are active in during times of invasion and helping the inhabitants of the planet in any way they can.
Angel worlds at first glance look like normal planets but upon closer inspection it is revealed that they have a huge field of heaven energy surrounding the planet. Many of the laws of physics and laws of reality do not work there as well because of them existing in a large globule of heaven energy. Animals of an angel world will also act friendly with humans who are loyal to the service of God but will relentlessly hunt down demons and their servants. Basically anything that is even remotely loyal to demons will not be spared unless they atone for their sins.