I mentioned before about Runes... these are Heroes & Castles form of a "soft" loot system. Runes can have 1 or 2 effects, ranging from bonus armor, bonus damage, healing abilities, lower unit costs, increased gold income, and a bunch more. In the future we'll be adding Runes that can imbue your weapons with fire, holy auras, and other effects that have unique properties only against certain enemies. There are literally thousands of combinations that you can find, and it is a cool way to further customize your heroes, even giving them a little flexibility beyond their inherent specialties.
Runes can be found after clearing a "stage", and come in many variations such as Common, Uncommons, and Rare Runes. Of course the more rare, the more powerful. Better Runes are easier to find as you progress through the game.
The second hero is the Paladin. The Paladin is a support hero, focusing on healing and making other units stronger. His attacks are highly disruptive, though not very powerful, and his health and armor are average. He has above average speed and running ability. His abilities range from a powerful, stunning blow called Retribution, to a Blinding Light passive which slows down all enemies in an area, to a powerful Holy Vengeance ability, which increases damage of all friendly units around him. Visually, the Paladin's abilities are a sight to behold, with huge light ray auras that give him a very "holy" feel.
His elite unit is a powerful mage, which heals all units around him while dishing out massive damage with powerful ranged magics.