a hero from an unknown timeline who fights using metal armor wreathed in flames and spiritron particles. underneath the armor, firefly takes the form of a young adult with pale hair and pink eyes, possessed of a quiet, friendly, and determined attitude.
they are a counter guardian, at the command of the world's will to survive, who fights against fragments of the corrupted grail to prevent mankind's destruction. their history prior to becoming a counter guardian is vague and fragmented, but they recall they were once in a grail war and fought alongside a valiant knight. above all, they have a deep desire to live.
in the year 2017, 48 people gathered in an antarctic observatory with the goal of investigating a ripple in spacetime. kam was one of the commoner mages selected to join chaldea's ranks, number 30. yet, just as each prepared to deploy to the singularities, a bomb exploded, disabling half the coffins and trapping the masters within, including those of the so-called 'A-team' intended to save the world. kam, among the rest of the masters, were forcibly rayshifted to fuyuki and forced to fend off not only the shadow servants but other mages in order to survive the singularity and return to chaldea; he summoned his first servant, an assassin, while being attacked by other mages--and allowed his servant to slaughter them, taking their command seals and servants for himself. when he returned to chaldea at last, he saw the world had been incinerated and wiped clean of humanity--and it would be up to chaldea's remaining masters to solve the singularities and restore the world to its former state.
kam is from an alternate chaldea where several masters and their servants work together in order to suppress and repair singularities. ritsuka still exists in this canon; kam will have a varied relationship with them based on their mun's preference. other masters from his timeline tend to treat him with a guarded attitude because of his reputation as being a murderer (even if he says it was self-defense) and a master of an assassin. unknown to him, kam is host to a daemon as the source of his magical ability.
light is a chaldea master, though markedly less talented than ritsuka is; they've suffered more losses, lost more grails to enemies, and had to watch their friend, mash kyrielight, disappear during the final singularity. still, as they walk into the lostbelts, they are not without allies: galahad alter, a distorted version of the knight who once lived inside of mash, has answered their call instead. despite such struggles, light is in love with humanity and humans, and affirms humanity's right to exist with each singularity culled.
as a master, light struggles to do basic magecraft, isn't as physically adept as ritsuka is, and can't command servants well. however, they have grit, they're hard to kill, and their instincts have been sharpened over the years. they're a romantic at heart, looking for friends and companions in whom to trust.
the ruthless queen of fairy britain who rules with an iron fist. she has a disdain for fairies and sees them as a disorganized, cruel class of people who only understand violence. she recalls every bit of the sixth lostbelt, and has appeared in chaldea so she might better understand the reason behind her kingdom's failure. she also has the memories of proper human history's morgan le fay, although their personalities are distinct. due to this, she has a lingering disdain for artoria pendragon, although she feels only a modicum of pity for artoria caster.
despite her reputation for cruelty and indifference, her heart still reaches out to those who have been abandoned by society or stand apart from it. she took in the fairy baobhan-sith as her adopted daughter and taught her the cruelty necessary to survive in the world of fairies; she allowed the fairy barghest to become her guard dog, and reach for a chance at happiness; and she acknowledged the skill and wish to live within the fragment of albion, who appeared at her court with a desire to protect someone. she appreciates the weak and unsightly, and allows them clemency. above all, she wishes for 'a home of her own', although she may have forgotten this in her desire for conquest.
deep in her heart, she misses her dear friends who once traveled alongside her.
once an engineering student from osaka, yuuya had joined chaldea for an apprenticeship, only to find once they got there that they had been entered into the commoner-application master pool, although they had little experience in magic save for a strange self-healing technique. they managed to make their way through the fuyuki singularity, adapting to the role of master the best they could, and subsequent
their personal magic, called 'conceptual erasure', functioned as a healing spell operating passively to erase wounds and pain. it would also erase painful memories, until yuuya's encounter with the count of monte cristo at the prison tower, who would safeguard even their most traumatic memories for yuuya's own sake. their magic drained their energy often, giving them a reputation for falling asleep in odd places. in the fourth lostbelt, their legs were mangled beyond repair by a blast of magic, and their conceptual erasure acted in self-defense, erasing their legs at the thighs. since then, they use prosthetic legs and sometimes a wheelchair to get around.
yuuya has a love of fashion, sewing, weaving, and fabrics, which they were dissuaded from pursuing early in life. now they create their own mystic code outfits from a variety of styles with the help of miss crane, whom they apprentice under.