Hero's loyalty by 15 when rewarded and is used for hero persuasion. Besides as award given to heroes, it can also be used in the Persuasion of rival heroes.
Lion Medals can be obtained by attacking valleys or cities.
The level of the valley is of minor significance, as any valley (from Level One and up) will drop this medal. Attacking Levels 1-4 Barbarian towns also give this medal.
The Medal can also be obtained by attacking a level 2-4 lake.
Other than by attacking valleys or cities, you can also obtain this medal through a Medal Box reward or purchase, or obtain them via spins on the Wheel of Fortune.