All three evil entities are technically the same supernatural being of darkness who is said to be the progenitor of all evil in our Omniverse. Some have said he is the personification of evil in the Omniverse. However an entity out of paranormal play, The Darkness, has that role. The Devil is a higher dimensional creature originally born directly by the hand of God as an Archangel of the light named Lucifer. His pride, and ego eventually caused him to question if his Father, God of the Omniverse, deserved to hold dominion over all things. Especially when it came to granting humans ascension to Heaven, and eventual Godhood thereby trumping the natural born Angels such as himself. They had a major falling out, and Lucifer fell from grace. He became the first fallen Angel, and he took 1/3 of God’s original children with him.
Lucifer transformed into a diabolical Arch-Demon who renamed himself Satan which means adversary since he thinks of himself as Gods equal.
His official title is Satan The Devil. Devil is the highest title a demon can hold, and it is held by the Emperor Of Hell. Hell being the fifth dimensional dominion of demonhood. This means that some other entity of evil could potentially hold the title of Devil. The title is honorable among demons but God chose to have it’s meaning be that of slanderer. Armageddon, the final battle of good vs evil, will feature Satan as a major player vying for rule of the Omniverse among others who wish to oust God from power to enact their own brand of regime change. Although as impossible as it sounds the only way to do this is by possessing the mind of God which is the very Omniverse within which we all live!