Ariakan is an interesting champion with limited usage. First off, being a level 8, it is the highest level hero for the Dragonlance world. This, and the propencity for having Dragonlance realms unarble to defend themselves mean he will show up often in Dragonlance world deck.

Ariakan's key power is to make realms defend themselves as level 5 heroes (heroes, as it doesn't specify a different type of champion). This power is not incredibly strong, and only should be considered for decks that carry few champions, mostly high level (especially since the realm champions are effectively adjusted level 8, as they get the world bonus).

Also, it can empower realms that can already defend themselves, granting an additional +5 bonus. This means some of the strongest realms are very tough. Examples include Lair of the Eye Tyrant (68/4th) starting battle at an adjusted level 23, or The Oracle at Delphi (6/IQ) at adjusted level 18.

This works very well for "championless" decks where all a player's realms defend themselves. However, outside of the mentioned themes, Ariakan won't show up in many decks, as it is tough to use a level 8 champion specifically not to go into battle (since risking his power means you may not have it when a realm is forced to defend itself).

This boosts the last ditch effort, which is how most players look at realms defending themselves, most prefer to use those 8 champion levels to win before it gets to that stage.