The following mainly comes from initial traditional tribes in general, not including tribes who have mixed origins and other case-by-case variable exceptions.
As one of the nine foundational tribes, the [Six-arms Demon Tribe] were initially as several of separated tribes who had common custom on worshipping certain six-armed deity. After receiving their own Grimm-form,
[Grimm-form appearance]
In said stage form of Grimm-form transformation, aside from "turning their sclerae's color from white into black" along with their iris will glow at a certain level,
black-outlined purple-central vertical-symmetrical white flame-shaped mark on central of the forehead
purple skin
In said stage form of Grimm-form transformation, aside from these above-mentioned appearance characteristics,
[Grimm-form ability]
In said Grimm-form, aside from negating Grimm's sense and mask said users’ "human/soul presence", making the said user seem "invisible" and "undetectable" to the Grimm which able to reduce the Grimm's attraction and even further decrease the Grimm's aggression and hostility tension toward the said user and having enhanced said user’s basic physical properties (including strength and durability) that allow them to have similar equal footing with huntsmen and huntress,
enhanced strength and stamina
(minor) healing factor
generate additional two pairs of pseudo-biological-texture arms (a pairs of arms are positioned on behind the shoulders while other pairs are positioned on behind between lower chest and upper waist)
(original arms first, additional arms later)
Combat Application:
When fighting as individual,
[Societal Aspects]
[Cultural Aspects]
Despite having the common custom on worshipping the six-armed deity, the detailed religion content on their six-armed deity have their own interpretation among each different tribes
six-arts
custom made upper clothes with two pairs of hidden gaps which are located on behind the shoulders and behind between lower chest and upper waist of the back respectively