Using GamePlayerBot aka the EpicDuel Bot you can definitely make tons of credits. You just need to click every dialog like The Attacks, Exit Battle, Level Up, etc.. You can make tons of credits doing this, at least 1,000 - 5,000 in a day probably more.
And if you set up a mage at low levels you can get on leaderboards easily with Lighting bolt thing and Fireballs.