Talk:Moon Cancer/@comment-33929439-20180302220235/@comment-30736282-20190305144937

It looks similar to the Digimon triangle of Data-Vaccine-Virus. Avengers are data, the (corrupted) substance of the Holy Grail. Rulers are the Vaccine, or antivirus, that corrects irregularity within the Holy Grail. Moon Cancers are virus that mess up the Holy Grail. Virus infects Data, Data can restrict Vaccines while being immune to it, Vaccine deletes Virus. Everything in this post is fanfic, because there's no in universe interaction yet between the 3 extra classes, but if you're willing to bear with me, then read on.

This might sound weird, but evil as they might be, Avengers are ultimately a product of the HG's wish granting function. Wishes are wishes after all, and it just so happen that someone made a straight honest wish to kill everything in their sight. Rulers are weak to Avengers because all they do is enforce the rule, and Avengers are not violating any. Moon Cancers are strong against Avengers because they screw with the Holy Grail itself, making Avengers effectively their plaything.

Rulers are only summoned when a HGW's integrity is threatened. A notable example is Apocrypha's Great HGW where the loophole "what if the 7 Masters refused to fight one another" is exploited. Moon Cancers (well, just BB so far) often exploits loopholes like that, or alter things to their liking, so they are prime targets for corrections.

Moon Cancers are major headache to fit in the lore, but the lore is a joke at this point so might as well make fanfics out of it. As seen in the CCC incident, Moon Cancers (who so happen to be BB) utilizes the Imaginary Numbers. I don't know if using the Imaginary Numbers is inherent ability of the class, or if it's because BB is an aspect of Sakura, so this might not apply to other Moon Cancers. There should be somewhere to read about the Five Great Elements, but basically, the Imaginary Numbers is the element that is not accounted for by the Moon Cell HG. This is *THE* loophole in the Moon Cell, allowing BB to make those shenanigans on the moon's far side. Now, this is where the lore became a joke, because assuming the CCC incident is an irregularity, the Moon Cell should've summoned a Ruler to take care of stuff, but it didn't. But assuming that a Ruler DOES get summoned, then that'd mean Rulers have a way to combat the Imaginary Numbers (if not then, well, Moon Cancers have no weakness I guess).

Keep in mind, those 3 are EXTRA classes. Meaning that it's not possible to summon them outside of a HGW. Meaning that they don't have the "Grand" designation. They are a dynamic unique to the Holy Grail based (a.k.a. artificial) Heroic Spirit summoning system.