Monferno is debatably the best pokemon in the tier. While I can agree with that, the people claiming it to be S tier I just don't see it that way. Scarf is amazing at what it does, thanks to its dual STABs being hard to switch into, Monferno can freely click U-turn and that is a great benefit for offence. While I could say scarf is debatably S tier, it's non scarf sets aren't up to that level. SD or NP can be very very threatening but its ok speed tier and lack of defensive utility unless it switches into a bug type move hold it back.