Christians see Satan as the deceiver, one who deceives people into falsehood and sin. They believe Satan makes people question their faith and lures them away with pleasures and wealth etc. for example the snake in the garden of Eden was Satan who tempted Eve to go against gods command and eat the apple. So he tempts people away from god command/Hukkam. This is basically identical to what kalyug is ??? But it seems in Christianity this concept has been personified and many Christians make it sound like some crazy individual "fallen angel" who is at war against god, which is absolutely bonkers. But overall its basically the same thing? difference is they have personified it ...
“the devil and Satan, the deceiver of the whole world . . . the accuser” (Revelation 12:9–10),
“the ruler of this world” (John 12:31), and “the god of this age” (2 Corinthians 4:4).