Halldor was the first seen to obtain the Rune Eye. While flying along with another comrade on a military plane, suddenly a burst of light occurred followed by the mysterious appearance of a storm. While on the storm unable to see anything, Halldor's rune eye appeared and with its power allowed him to see through the storm and prevent them from crashing into mountain. Long after this event, Halldor found Odin's card on a tree root. The rune in his eye is an "Ash" symbol, meaning "One of the Æsir (gods)".
Dragan obtained his Thorn rune after obtaining Thor's card, though he didn't keep or use the card then. While climbing a mountain, an avalanche came down, the Thorn rune protected him from being hit by it. Halldor soon came with his helicopter and convinced him to use Thor. The rune on his eye is a "Thorn" symbol, meaning "the god Thor".
Broder was the last one to obtain his rune after stealing Loki's card. While trying to escape with the card, his boat crashed against a boulder and sent him flying into a pillar of rock and almost crashed. However the final rune eye appeared on his eye and a thunderbolt appeared from the sky to destroy the pillar. The rune on his eye resembles the "Hail" symbol, also meaning hail (the precipitation).
The Rune Eye shares many similarities with the Crimson Dragon's birthmark.
It allows Halldor, Dragan, and Broder to use the power of the Aesirs, as well as represent a connection with these cards and to each of themselves respectively. It protects them from any dangers or threats.