New character thanks to chapter 3 of Child of Darkness.
Sayik is an ancient Garo shaman with massive magical power. He has use of both light and dark magics, from basic healing to raising the dead.
Like Azize, Sayik is probably dead. His eyes glow in darkness, but his tattoos are just regular tattoos.
A bit on the Garo of my Hyrule:
The Garo, in my Hyrule, are based loosely on two aspects of the Zeldaverse: The Sheikah and Kafei.
Kafei, being the only one of his kind in the games, with purple hair and red eyes, I figured that he was Sheikah at first. But I got to thinking, what if that's what the Garo looked like when they were still alive (assuming, of course, that the Garo in-game are in fact spirits)
The Garo in my Zeldaverse originated in the same bloodline of the Sheikah. The two groups became what they are the same way humans irl did; location, upbringing, environment, etc. The real differences between Sheikah and Garo are that where Sheikah are dark-skinned, pointy-eared, and light-haired, the Garo are light-skinned, round-eared, and dark-haired, most commonly with purple, blue, or black hair. (Sheikah, in my Zeldaverse, have white, silver, pale blues or reds, and blond hair) Both groups have red eyes.
The Garo, like the Sheikah, are very secretive, but instead of working for others (Like the Sheikah in service to Hyrule and its royal family) They kept to themselves. They are also heavily rooted in magic, self discipline, and perfectionism.
The major difference between Sheikah and Garo is that Sheikah come in different sects, where as Garo are one big secluded group.
Okay, I'm going to try and shorten this now that I can update, because I'm going to lose all the info in my brain if I take too long.
The Garo are big on being strong in body and mind, so they train and educate themselves. As the tribe grew, so did their stone tower, which acted sort of like a home base for doing just that, training and self educating. Being in a canyon, they had to build up instead of out to stay hidden.
So, as they grew more enlightened, they figured they could ascend above all others, even to the level of Gods. They built their strength, built more on their tower, and tried to reach the heavens. This ties in somewhat with some Twili theory.
Anyway, they gain more power, they gain more notice from locals, like other Ikana residents. When feeling threatened, residents form an opposing force. The dead soldiers in Ikana graveyard? That's the opposing force.
Opposing soldiers outnumber Garo, though Garo are far more skilled. But fear of Garo secrets getting out makes the Garo paranoid. They try to use forbidden powers in the tower while there are soldiers out about Ikana fighting off the soldiers, but since said power is forbidden, Goddess intervention is in order. All the Garo that are in the tower (which is anyone that's not an assassin/soldier/on the battlefield at the time) gets banished to an alternate realm in one mass washing sort of thing.
Those left behind are left to fight the overwhelming forces on their own. They retreat to protect the tower, and actually succeed in doing so, but are all killed off in the process. But the Garo never give up, so their spirits remain in the Canyon to protect the stone tower and the Garo secrets until the end of time.
The reasoning for Kafei getting away follows the Garo system of punishment. There are two ways to deal with crimes in the Garo tribe, death or exile. Death is quite self-explanitory, though it usually is followed by a sort of Garo version of a Shaman sending. They send the spirit away, seeing as they know how stubborn Garo souls can be. Exile is for not so much crimes, but more so bringing shame to the clan. If a Garo is sent to Exile, they are to have their hair cut (not allowed to cut their hair in my Zeldaverse) and either tongue or vocal cords removed so they can't tell anything.
One such person would be a recent ancestor of Kafei, probably great grandparent, Meaning Kafei isn't full Garo, but the last living being with the Garo bloodline.
To go into Twili theory briefly, MY theory is that the Twilight realm was a final place for big time criminals that were banished by the goddesses, because they don't like to kill people, just send them elsewhere where they can't do any damage. Anyway, the Garo are mixed into the Twili bloodline, as well as Gerudo, Sheikah, and Zuni (yes, I include Zuni since it seems as though FS and FSA has been place somewhat near the begining of the ever un-official Zelda timeline. Let's just say it's my timeline, formatted for the purpose of my own stories.)
The ancient tribe that used dark magics and the Majora's mask, that would be Zuni. Zuni have blue skin and share a desert with Gerudo. The Zant look looks like a Garo leader, and they have very similar traits (hiding swords in the sleeves, helmet and tongue symbol on helm, oversized clothing.), Sheikah are a big part of just about anything that deal with shadows, and their symbol appears on the back of Midna's helm when completed (my theory, some sect of Sheikah that didn't take Hyrule's betrayal so well tried to undo them, and goddesses weren't happy. I belive Hyrule is to Goddesses as Israel is to God...which I guess would somehow make Hylians Jewish or something... O_o ) and the Gerudo, after Ganondorf's early fiasco in OoT, were punished for messing with the goddesses' Hebrews. All four groups were sent to the Twilight realm at one point or another (for me in the order of Zuni, Sheikah, Garo, Gerudo) and after many many centuries of mixing cultures, races, and the inclusion of an almost completely dark world, created the red/yellow-eyed, red-haired, tall blue-black skinned people that are the Twili.
I think that's all I have for now. If you have questions let me know.