Harry Potter and I'm bad at titles

Slytherin!Harry. Most likely Dumblebashing will occur. I know I go away from canon in a lot of the specifics which is because these are things that are either needed for the plot or things that I believe are canon. I have a plan for this story that should occur around year 3, so pay attention for that. I most likely messed up here so please review and tell me how I messed up.