"It seems that the effects vary depending entirely on the symbol. This has lead me to believe the Marks are more than just symbols. They hold powers untold, powers I plan to control."
Created by a Toa known as Arekule by the re-purposing of a rare metal, Krillactum, a Mark will give it's Bearer enhanced strength when active.
Arekule, a Toa of Sands initially began looking into the Rune upon discovering a hidden temple of the Kumu-Islets. After doing some sneaking around Turaga Nuju's things, he discovered the Turaga had some information on it written long ago. After suspecting a weaponized version of the Mark's were achievable, Arekule attempted branding many beings with a metal he found with the original notes; krillactum.
Many test subjects died in the proccess. Upon succesfully branding a test subject, he started to search for more "candidates". This spurred the complex and chaotic journey the Mark Bearers would soon take. Arekule documented his findings in a journal Tank and Utu, respectively the Bearers of Pain and Fear, stole from his assistant Kearrstrun.
A Mark is tailored to a specific emotion, and it feeds off it. The amount of strength that's passed onto the Bearer is entirely dependent on the amount of the emotion is in the area.
A Mark of Anger will not have any effect on it's host until active. Any and all anger, even the anger of the host will boost the strength of him/her. It may exceed the strength of a Pakari, or even just enough to lift objects easier; depending entirely on the amount of anger.
Marks will glow when active, and cause the host's eyes to glow the same color.
The Mark will activate on it's own if it is not fed often, taking control over the host's body in order to feed itself. Forced use of the Mark is painful, and impossible to stop.