Her R+Q deals insane amount of damage no matter which phase of the game we are in. Her W is a bit different than other enchanters' CC abilities, we need to be around our enemy for root to work. Onto out main ability, first off, Karma has a pretty solid mobility/defence ability which has almost no cooldown, we are talking about her E.
This ability allows us to freely engage/disengage our enemy with almost no damage taken, this is our main ability which lets us build this up.