Ersahi is the name of one of the three currencies used in the two kingdoms of Naiakana and Nareikk, and is the least valuable of the three, equating to a quarter of the primary currency, Darih, and half of a Danisi.

Ersahi are used infrequently in Nareikk and Naiakana, and thus are mentioned very sparingly throughout Violet Sword Blade, a book in the Untaer Archives which takes place in Nareikk. Their low value means they are not dealt with much in trade, though the protagonist, Mazzek Rettensauth, buys a cake from a woman in Persinai for two Ersahi.