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 whose tribal homelands were located around northern snowy mountainous region of Anima continent while having common custom on worshipping certain six-armed deity whose exact context is more or less similar between each one nonetheless. After receiving their own Grimm-form and then returning to their own tribal homelands in Anima, they started to started to build and spread out their own influence range across the whole Anima continent (including Spiky-vine Archipelago) via either military mean (including launching several raids on other non-[Six-arms Demon]-settlements (whether from Grimm-folks or nor) within Anima continent (mainly, If not almost, focus on those on land surface)) or having political marriage with other (mainly human) settlements for as the exchange for either the discontinuation of raiding said settlements and leaving these settlements alone. And then, for many those [Six-arms Demon] tribes who married with original (mainly human) residents from the other local settlements in the [Six-arms Demon] tribes’ expanded zone, the said [Six-arms Demon] tribes’ original cultures began to introduced/merged (or even highly assimilated) with the cultures of original (mainly human) residents from the other local settlements and then later became their own independent cultural-social entities, who are highly different compare to their original one, within their own lived territories of their own different environment in many different region within Anima continent (along with increasing rivalry relationships between each [Six-arms Demon] tribes as well), besides some of these [Six-arms Demon] tribes start to build and maintain decent trading relationships with other eastern (Anima) Grimm-folk tribes, such as [Perfume succubus] tribes, [Darkvine plantman] tribes, and [Blackmud demon] tribes, for keeping positive the exterior relationship with other eastern (Anima) Grimm-folk tribes at certain level along with exchanging various goods. And then, when around the beginning of first mistral empire era, despite there were few of (mainly from southern-west region ones) [Six-arms Demon] tribes having several crashes with newly-birthed first mistral empire (especially on military ones) including the ones fought within the Anima inland sea when first mistral imperial naval force fight against certain invading multi-tribal coalition naval force which mainly consisted of some southern-west [Six-arms Demon] tribes as the leading force along with few of other eastern (Anima) Grimm-folk tribes (including [Darkvine plantman] tribes and [Tree swinging fabric-strip demon] tribes) as supporting/assisting force, most of (including the northern ones) [Six-arms Demon] tribes had generally good relationship with first mistral empire and usually came to first mistral empire for either trading or studying and learning from the first mistral empire such as cultural learning and several advanced material-crafting/blacksmithing techniques, as well as there were even few of certain individuals work as independent hired/voluntary mercenary that fought along with first mistral imperial military, and then after their several interactive contacts with members of Mistral's Four underworld families (especially Northern clan as their first interactive object), many of (especially those from the northern region) [Six-arms Demon] tribal members have shown their own interest on Mistral's Four underworld families and participated under the ruling structure of Mistral's Four underworld families. And then during the period between first mistral empire era and second mistral empire era, many of [Six-arms Demon] tribal members were already lived under the ruling structure of Mistral's Four underworld families, particularly in {Northern clan}, and there were even increasing numbers of [Six-arms Demon] tribal members moved across further to Mistral’s capital area's east side and then joined and lived under the ruling structure of {Eastern clan} of Mistral's Four underworld families. Finally, after the implementation of "nighttime-wandering order", asides from there are most of their own tribes (including those from Spiky-vine Archipelago) still living within their own (original or expanded zone) tribal homelands in Anima, there are no any significant impacts on their tribal daily lives despite having previous damages caused from those interior conflicts between Mistral's Four underworld families after the Great war as well as the relatively chaotic situation of their "clan leader" 's families in Northern clan of Mistral's Four underworld families when was occurred at around the end of the Great War, and still continue on both their commercial activities and daily lives within the Kingdom of Mistral's capital as usual. Besides, there are certain amount of [Six-arms Demon] tribal members come to Mistral’s capital for either commercial activities, learning (such as martial arts and usage of Aura), visiting their own tribal member who live within the Mistral's capital or sometime have their own tour on certain large-scale underground urban district of {Eastern clan}'s Grimm-folk tribal members below the {Eastern clan}'s said turf, and even some, especially younger individuals, come to Mistral's capital and have some life experiences of living among Mistral's civilian daily lifestyles.
[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, a black-outlined purple-central vertical-symmetrical white flame-shaped mark is appearing on central of the said user’s forehead, also the skin color of said user’s entire body are changed into purple as well.
In said stage form of Grimm-form transformation, aside from these above-mentioned appearance characteristics, additional two pairs of Grimm-like matter-made pseudo-biological-texture (one (human-like one-thumb-and-four-fingers-included) hand per arm) arms are generated from the said user's back, that one of pairs of additional arms are positioned on behind the said user's shoulders while the another pairs of additional arms are positioned on behind between lower chest and upper waist, making the said user's appearance in said stage form having the physical trait of six arms in total.
Note: these muscle shapes of generated Grimm-like matter-made pseudo-biological-texture arms are dependent on the said user's current original arm-muscle shapes (e.g. said user's arm-muscles becoming more muscular after certain intense gym workouts). Besides, generally speaking, assuming both genders receiving same level of physical training, the said male users' muscle shapes of generated Grimm-like matter-made pseudo-biological-texture arms are apparently more muscular compare to their female counterparts.
[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, under having generated-from-user's-body additional two pairs of Grimm-like matter-made 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), the said user also able to manipulate six arms (along with three pairs of hands), granting the said user independent, simultaneous control over all six of the said user's arms (along with hands)
enhanced strength and stamina
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)
Note: In terms of (both original and later additional Grimm-like matter-made generated) limbs movement prioritization at will, the said user's original limbs have higher movement priority compared to additional Grimm-like matter-made generated ones, so in other words, the said user able to use six arms at will when in Grimm-form while without being interfered and complicated by later additional two pairs of Grimm-like matter-made generated arms.
Besides, said user also has access to regenerative healing capability that able to heal up either at least large amount (at least twenty) of piercing wounds which go through the chest caused by large throwing spear, certain amounts of piercing wounds which go through the chest caused by some concentrated musket-ball volley firing or at least four to five piercing wounds which go through the chest caused by towering-tree-trunk-wide ballista-launching spear, though these wounds which are higher than above mentioned wounds need additional amount of medical care for the purpose of accelerating the healing process. Besides, regenerative healing performance in completed form of Grimm-form transformation is obviously better than in partial form of Grimm-form transformation, though not better than [Oni demon].
Combat Application:
When fighting as individual,
can strike multiple opponents or hit a single target with a barrage of punches at the same time
coordinates all six fists to strike from multiple angles to overwhelm foes in close combat
When fighting as group,
Because there are high numbers of [Six-arms demon] Grimm-folk tribes that are impossible to list them all, these following introduced [Six-arms demon] Grimm-folk tribes will be cataloged according to the approximate regional cultural sphere where these said tribes' lived in.
[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
[Societal Aspects]
[Cultural Aspects]
[Societal Aspects]
[Cultural Aspects]
[Societal Aspects]
[Cultural Aspects]
[Societal Aspects]
[Cultural Aspects]