I mean, if you Birds, Beasts, and Fish. In mythology, the Leviathan and Behemoth are associated with one another. If you have a Beast Rune, doesn't it follow that you may have a True Rune governing aquatic creatures and maybe a true rune governing avians?
A Beast is a beast. If there would be seperate True Runes for Birds, Fish, Reptiles then we no longer need to speculate. The Beast Rune dousn't even nessicerally govern beasts, it at least governs animalistic rage and passion.
The Hachifusa Rune is a true rune. Yuber bears it and has a special relationship with Peshmerga. WOuldn't it make sense for peshmerga to also bear a true rune? As Yuber is associated with destruction and all the bad things that happen when taoist principles are out of balance, perhaps peshmerga exists to maintain the balance? something like that.
Pesmerga needs not bear a True RUne. Thats just fanboy mentality.