Note: This Guide was inspired by Kerdax and Moby Michaelis on the forums.
The Chronicles of Merlin is an RPG (Role Playing Game) with RTS (Real-Time Strategy) aspects built in. Therefore there is not one correct answer for which Hero is most powerful. Instead it is a combination of things that will result in the success of Battle. The following are some tips to succeed in Battle.
Know which type of attack your Hero uses. There are 3 types of attacks: Normal, Gambit, and Spell. Siege units only have Normal attacks, Gambit users have Normal attacks and Gambit and Spell Casters only have Spells. It is also important to note some Gambit users are Defensive and instead of having an attack their Gambit will consist of debuffs for Enemies or Protection for themselves.
Know the differences in the Attacks. Normal attack is very consistent but it has low damage and can be blocked or dodged. Gambit is very powerful but it can take time to build up Morale and it can be dodged. Spells cannot be blocked or dodge but success rate is not always very high.
Know how to use Support Heroes. There are three types of Support Heroes: Flag Bearers, Priests, and Healers. Flag Bearers increase all Gambit users Morale by a set amount, Priests fill a random Gambit users Morale full, and Healers….well they heal or add a certain amount of units that you have lost.
Know how to Gear your Heroes. If you are using a Gambit user that has a Gambit Attack, then a Horse is most important as they increase your Gambit attack. If you are using a Siege unit then you will not need a horse, and will rely on your weapon. For Spell Casters your Enchanted Item is most important as it add Spell Attack, they will not need Horses or Weapons. Your support roles will not need any sort of offensive weapon. As for the other pieces of armor you might want to look at your formation see who is in a Defensive role or is on the front lines, but you will need to take all Heroes into consideration as they all can be hit.
Learn to read Battle Reports or Strategy's. This is VITAL no matter what level you are. This will help you understand which Formations counter which Formations, and which Heroes are best used against which formations or other Heroes. Visit the Battle Report Forum.
Learn Formations and how to counter other Formations. Learn how formations work, who goes first and what special bonus’s they offer. Learn where to place your Support Heroes so they offer the most benefit to your other units. Also make note of the enemy and who goes first on their side, where their main attackers are, and how to get rid of the most important first.
Max out your Research. Do not forget to max out all of your research as they offer hefty bonuses. Almost all of them are important but if they do not pertain to your Hero you can leave it out. For example if you do not have any Spell Casters, you do not have to level up Alchemy.
Increase your Hero's Attributes.
Pay attention and Increase your Hero’s Attributes with Enlighten. These are Bravery(Normal Attack and Defense against Normal Attacks), Tactics（Gambit Attack and Defense against Gambit Attacks）, and Magic(Spell Attack and Defense against Spell Attack). By using Enlighten you will randomly increase these Attributes, Gambit users will focus on Tactics, Spell Casters on Magic and Siege on Bravery.
With the right combination you can beat anyone even enemy’s a lot higher level than you. Just look at the following Battle Report: