Attaches only to coastal realms. Only undead champions may pass Charon. Others need to pay the price - sacrifice a champion to attack that realm.
Art by: Edgaras Guršnys
Flyer - Champions or allies with the ability to fly can attack any realm, regardless of its position, by flying over intervening realms. If a card does not specify that it's a flyer, it is not, even if the picture shows wings or the name of the card implies the ability to fly. Flyers cannot attack realms that specifically state that they are immune to flyers or that flyers cannot attack. The ability to fly is not automatically granted to allies unless it specifically states so on the flyer's card.
Earthwalker - A champion or ally with the earthwalking ability can travel under the ground to attack any realm in a player's formation. Earthwalkers cannot attack realms that specifically state that they are immune to earthwalkers, or that earthwalkers cannot attack. Earthwalkers cannot attack realms that specify that only other types of champions may attack (such as "Can only be attacked by clerics" or "Can only be attacked by flyers or swimmers"). The ability to earthwalk is not granted to allies unless it specifically states so in the earthwalker's card
Swimmer - A swimming champion or ally can attack any realm in an opponent's formation that shows a coastline in its picture. This also includes realms with pictures instead of maps that depict coasts. The ability to swim is not automatically conferred to other cards, so a champion attacking a protected coastal realm must have the means to get his allies there if he intends to use allies in the round of battle.