You have three chances to roll an epic general when you start a new account. In my testing, the odds of getting an epic general was about 1 in 30. So these means you will need to create on average about 10 accounts. Each account should take 3 minutes or so to create, and roll your general chances.
Start a new account. Quickly run through the tutorial which should take about 30-45 seconds. Change your realm to the realm you want to play. On the new realm enter the officer's quarters. You will be required to do a small tutorial on generals which includes hiring two generals and enhancing your rare(blue) general. This takes about 45 seconds.
Once you have done the tutorial exit the officer quarter and go to your quest log. You will gain to level 6 or 7 and have several quest completed. The reward for some of them is 3 recruiting tokens. Go back to the officers quarters and hire the three generals. If you get a epic(purple) general you will gain enough power to get to level 10 or higher and you have access to arena and an epic general. If you don't get an epic general you go to the account settings, create an account and put in a bogus email address and password.
If you are on android you go to your app manager and clear the data. This resets your game. The next time you log into Dragons of Atlantis Heirs of the Dragon, you will have a fresh game. Repeat the above procedure until you get the epic general you want. You now have a guaranteed free epic general.
Once you get the hang of the process you should be able to get an epic general in 30 minutes or less. It is well worth the time to do this when you start a new realm. Having an epic general is a huge bonus at the earlier stages of Dragons of Atlantis Heirs of the Dragon.
Here is a more in depth explaination How to get free epic general.
Here is a more in depth explaination How to get free epic general.