Okay here is what we know:
1) Three locations with Odin's Illusionary Rune have been shared.
2) "Odin's Illusionary Rune was used to make the bearer invisible or shape shift, such as the Viking berzerkers who took on the form, strength, and courage of bears in battle" according to a google search.
3) "Originally berserkers developed their own brotherhood of professional l warriors who travelled round and took service with different chiefs. What distinguished them was that they had bears and wolves as totem animals, and clad themselves in their skins. Irrespective of whether it was a bear or a wolf, the warriors believed they were endowed with the spirit of the animal." according from another internet search.
4) " Odin is particularly associated with wolves, ravens, and horses." according to another google search.
5) Thus far, all the runes have been on rock structures.
With all that being said, I tried a few things. I chose to experiment with the symbol located in the southern coastline. I have switched gear attire and weapons: Berserker Gear and Raven Clan Gear. Tried to going berserk (wailing my weapon incessantly) while in having max adrenaline. Used Excalibur and other mythical weapons. Mediation right afterwards, then tried mediating incessantly. I later switched to Noden's Arc and used Incendiary Powder Trap skill and it blacked out the symbol. Long ago I used the explosive arrow with a different bow, there was no explosion and the arrow was just stuck there. Now I did not the chance to try it again with a different bow to see if the result was still the same. I plan on playing again later tonight to search for more Odin's Illusionary Runes.