Demon's is either the hardest or easiest. Pure melee, it's the hardest game in the series. Include any magic and it's a cakewalk. it's still my favorite though.
Meat cleaver is still technically pure melee and that is one broken ass weapon
I feel like Dragon Bone Smasher is broken too. After I got it I could just one shot everything pretty much. Even bosses were going down in seconds.
It does absurd damage and blows over humanoid enemies, but it still requires it's own finesse since the lack of poise means that you'll get hit out of attacks if you are off on your timing. That's what makes the Meat Cleaver so nuts; you can absorb attacks with it and still swing (plus the healing and scaling).
Unless the Dragon Bone Smasher can do that too, in which case swing away. My memory is a bit fuzzy on which weapons can. The only one I remember for certain is the Crescent Axe because it's rad.
Maybe consider looking into Smite. It's much easier to get into (fewer items, fewer characters, etc...) and the games are generally faster. It is the Dead or Alive of MOBAs; the best starting point for people unfamiliar with the genre. Playing an easier game will also help you transition into the more complex ones when or if that happens.
Also, as others have mentioned. The real key to getting into these kind of games is having other people to consistently play them with.