Here is what I found on a coment on reddit: I can't help but feel like most of these replies aren't really grasping the entire concept of divine spirits properly, so here goes According to Babylonia, under normal circumstances it's only possible to summon a Divine Spirit during the Age of Gods. This is presumably because Divine Spirits are basically remnants of the actual gods who lived during the AoG, so obviously a modern day replica could never come close to the original. Which brings us into the next big thing: bunrei. Again, according to Babylonia, any Divine Spirit summoned is considered a bunrei (or wakemitama) of the god. In the most simplistic terms, this basically means that they are not the original god themselves, but a copy. This means that when you have a case of, for example, a god who gave up their divinity to be summoned, then the literal god didn't lose their divinity to be summoned, but rather the *copy* of them lost their divinity. You then have the whole part about who counts as Divine Spirit and not. First of all, Divine Spirits are the gods of old who lost their power (to some degree) and basically degraded into Divine Spirits (and subsequently had to move to the reverse side). However, this didn't affect *all* gods, and some of the more higher ranked ones still exist as "themselves". The most common example of this is of course Amaterasu, who still exist within her own dimension, and so as she's technically still "alive" or however you'd like to call it, there's the possibility that you can't really summon her directly (though of course you have Tamamo in her stead). For anyone "ranked lower" than that, for example demigods who became proper gods after death, avatars of a god, bunrei, or you're related to a god somehow, and so on, then you simply get Divinity as a skill (which refers to the aptitude one has for divine spirits). Those who fall into this last category are of course not "limited" by the summoning system in the way that the aforementioned are. And finally, an important aspect of Divine Spirits, as someone else mentioned here, is that they have Authority. Authority is the sort of power that you'd probably think of when you think "god powers", like alteration of events, world creation, controlling flow of time, etc. Divine Spirits can use Authority, but those summoned by Chaldea in FGO *can not*. A proper example of this is Quetzacoatl, who has Authority during the events of Babylonia, but not when summoned in Chaldea. --- Now then, regarding actually summoning Divine Spirits... * You summon them directly, basically having the actual Divine Spirit give an "ok signal", and then you can summon a bunrei as explained above. This is stated to not be possible under the Fuyuki system, and even in Chaldea's case I recall Roman actually saying "it *shouldn't* be possible", so there's obviously some leeway, and if you're writing your own story it doesn't really matter much. * Pseudo/demi-servant. Such as the case of Ishtar. You just summon the god (again, technically a bunrei) into a person with matching characteristic and whatnot, instead of having them materialize like usual servants would. * Some sort of "possession", which sort of falls under pseudo-servants. There is a case of this in Strange Fake, where [](/s "Fillia is actually possessed by Ishtar because of some mysterious events, and because she is a homunculus with a 'blank slate' for personality, the character is basically 'all Ishtar'.") and probably some third point I'm forgetting right now. Then again, you probably don't need to go much deeper than this if you're writing your own story, as long as you at least try to give sensible explanations as to why it works. I also sort of wanna ping /u/waifuhunter here, as he definitely knows more about this than I do. EDIT: The third case I was thinking of was likely Artemis, who simply hijacked the summoning of Orion to be with him, but that's definitely not a standard case. This is what heroic spirits are: Heroic Spirits (英霊, Eirei?, localized as "Legendary Souls") are Spirits of heroes who achieved great deeds in life, having become objects of worship after their death

In my opinion giving the mc a mahito template having it at 100% and the mc not being able to do what mahito does is completely stupid, healing some eyes should be eazy plus the mc being so stupid when he is danzo son is crazy, danzo would 100% train his early to make his a good ninja or to have gim get a very good base at the start of the academy,plus why didn't he leave a clone or a note for reine if he left to train.

I'm pretty sure alaya takes the soul of heroes and those with legends and puts them in the throne

this is not Canon,kuroka and koneko were under a devil that experimented on his servants to make a super devil,so kuroka killed her master because he wanted to experiment on koneko,and left koneko at the gremory and left,there was not any nekoshou village because the are very rare and are on the brink of extinction and the yokai live in kyoto. if you didn't know, but maybe it's part if the au l.

minato is a civilian so he doesn't have any bloodline,

gojob with infinity can't be moved by an attack because the attacks didn't touch him,limitless makes it so that there is an Infinity distance between the Caster and the attack

there is no such thing as satan class

serafall would have been in a suit not in a magical girl outfit

otsusuki have perfect chakra control

of corse to kill him,why would a servant attack a master.

why would u make her this stupid,she would remember that he fought lancer and the masters face

of course it is violent its a war,and you could have given your command spells to kirei,nobody forced you to participate.

is he going to tell every master to form an alliance?

why would he go alone, and why was he a retard and didn't cover his command spells when it was written in the note?

So somoane comes and wants to kill you,and you propose a alliance which is stupid,you don't know,them they could betray you the moment you let your guard down.

how could he have the jougan and i don't think the hyuga would give their taijutsu just for this,

why are you making this a shirou x saber?

Are you speaking about the uchiha because and I don't remember any civilian throwing fireballs at 4,

The only children that awaken their chakra are those that go to the academy and from ninja clans,isn't it said that children awaken and train their chakra in the academy? and it's not like you can go to a normal library and learn how to mold chakra and the academy jutsu,plus it would feel more natural if he tried to see if somoane from the orphanage is in the academy to try to get him to help,I'm just saying that it would be suspicious if nobody tought him and he would have that knowledge,and it is said the he trains in the garden.

he needs reiatsu to use a Zanpakuto,how is he going to do it if he dosent have any?