When you recruit a hero in Undead World: Hero Survival, they have an innate rank of Common, Rare, or Epic. Common heroes cannot increase in rank, only in level. The others can progress through a series of ranks to reach their ultimate potential. 

Epic heroes can ascend to Legendary Plus. Rare heroes can ascend to Unique Plus. There are multiple ranks in between the initial and ultimate ranks. Ascending a hero's rank will alter their icon accordingly. Learn all about Ascension in Undead World: Hero Survival.

You can quickly identify a hero's rank by the border color around their icon. 

	Common heroes have green borders.
	Rare heroes have blue borders.
	Doc starts out as Rare with a blue icon; in this image, he has been ascended to Rare Plus and gained brackets to indicate his new rank.
	When you ascend two Docs of Rare Plus rank, they form an Epic Doc.
	Epic Plus adds golden brackets to the purple border.
	Unique heroes have a golden border.
	Unique Plus adds golden brackets to the golden border.
	Legendary heroes have a red border.
	Legendary Plus heroes have a red border with golden brackets.
	Mythic heroes have a silver border.
	Mythic heroes gain stars at the bottom of the icon as they rank up further.
	This hero is at his maximum rank and cannot ascend again.

Limit Break

Each hero rank has a max limit to which it can be leveled up. That limit will increase as more of your heroes achieve Mythic rank. When you see the LEVEL UP button on a hero's detail view turn into LIMIT BREAK, that means you will not be able to level up that hero again until you have more Mythic heroes.