The Coven Leader was always into magic, (Commas should not be followed by a capital letter) She loved witchcraft at home. (Your saying, and not showing. Instead of telling us what the Coven Leader likes, show it. Not "she loved witchcraft." Instead, do something like "She would spend her days learning the arts of dark magic.") She didnt (apostrophe?) know much but read the books. One day, she tried a spell and it worked! (This should be more dramatic/longer)She decided to move to a peaceful town to play some pranks. Why not? (This is not a reason. This is an excuse to frame a certain story)

As soon as she went to Salem. (This is an incomplete sentence, you would need an action after "As soon as") She saw something else. She sensed it with her magical powers, other beings just like her is around here. She moved and stayed there for years. Soon figuring out as a solo figure (What does this mean? Read it to yourself), she encountered the mafia (Capitalize the "M"). She had the Godfather as their idol, it was her dream to make a team and to be a powerful force. One day, she found the magical beings. They were specialized and they loved playing pranks, they gathered together and started to work. They than made up the name, "The Coven"(period needed here)

The Coven started to grow in power, learning more and more. She than (then, not than) understood what was the purpose of her life, to kill. (How? You didn't explain this!) She wanted to wipe the town. Everyone infact! The team went on the rampage to destroy all of the town members. One by one..  (But did the team want to kill everybody?)

Days and Days (the second "Days" shouldn't be capitalized) later, It (this shouldn't be capitalized either) was the Godfather, their idol and their consig, (wait so who's "herself"? the consig? I think? Clear it up, because the commas frame this sentence like it's a list of people, not a list of people with a description of one person thrown in) herself, and the medusa ("Medusa" or "the medusa". This is just your preference, I assume). The Coven Leader had to kill their idol... That (lowercase needed here) night, she used her power to drain and move the consig to the medusa. The next morning, the consig was dead. (lowercase-ize the "T" in "The") The godfather (you first capitalized "Godfather" but now he's in lowercase.) started to look up and smiled. (Why?) He nodded and let himself get burned at stake. (When did he get put on the stake? Why is he smiling/nodding?)

Im (Apostrophe needed here) not sure if this is decent at all XD ("XD" is not a proper word) (improper capitalization) (period needed here)

yes I know that I had/have inconsistant capitalized letters when starting parentheses.