Unhealthy relationship.Any advice?

i recently became online ''friends'' with a man and i think everything heads in the wrong direction.i met him through an online game.he told me he needs someone to explain him the game,so i agreed to help him and added him in the buddy list,as he was from my country.he told me he is 40 years old and i'm 15.as long as i helped him,he was very sweet with me.he contacted me everyday and he added me in his messenger list.but one day i was playing with another friend and told him i can't help him right now and he became furious and told me i'm ignoring him and deleted me from the buddy list.a couple of days later i tried to explain him why i didn't help him and he didn't want to understand he said i was ignoring him on purpose.he was making stupid jokes i don't like:be a nice kid,grow up,go to bed and sleep rather than talking nonesense,shut up or i'll beat you.i tried to explain him i'm not a little stupid kid,but he didn't want to listen so i called him old man.he became very furious and told me i have no right to call him that,he was just joking ''nicely'' with me.he then showed me a photo of him and told me to wait until he finds one with him and his daughter.he told me he can't find it,so he showed me one with her and her mother.i told him his girl is cute,but nothing more.he couldn't accept this,as he thought she is very beautiful,but i told him this is my opinion.then he asked me how i look like.he wanted too see a photo of mines.i told him everybody tells me i'm really beautiful.''and very self-centered'' he told me.i mean i'm shocked after this convo with him.i didn't expect him to be like this.i did nothing wrong but tried to help him.everytime i tried to tell him how i feel he didn't want to listen.he spends around 6 hours per day playing that game and talking on messenger.considering this,how could he have a wife and daughter?when could he spend time with them at this rate?i talked about this with an adult and she told me to break contact with him as i already entered a dangerous game made by him.she doubts he has a family and is normal.she even think he could be a paedophile.i don't think the women from the photo were his family.please answer.i really need your opinions and advice!!