WMG: Mahouka Koukou no Rettousei
Analysis is Tatsuya's Origin
Onwards here be facts (and possible unmarked spoilers):
1) Magic is hereditary, there are pure-blood families who cultivate magic affinity:
: Tohsaka, Matou, Einzbern, Aozaki, and many others.
10/100 great families in Rettousei
2) Heroes who have no heritage and also have troubles with whatever is considered normal and usual:
- Emiya Shirou is a first-generation mage, unable to do even simpliest "Read item's inner structure" magic without completely draining himself.
- Shirazumi Lio is a normal high-school student, who is constantly dissatisfied with his life, feeling that it's not normal for him.
3) Origin is the concept that gives original birth to one's soul, and empowers it (not unlike True Vocation/Mission/Purpose of Existence)
- Shirou being "Sword", his only true magic is creating a subdimension filled with a near-infinite supply of copied legendary weapons.
Other applications, from easiest to hardest, include: instant analysis and recreating legendary weapons at one glance, copying common items, reading common items' structure.
- Lio, being "Consumption", was always born a predator, and once happend to be born as a human. After understanding his true idea, he began killing people and eating them, getting his consent with life back.
Though, superhuman speed and power, 10-meter jumps and an ability to catch a thrown knife in the air with your teeth and SHATTER IT also aren't bad.
The whole idea of the Origin is, like Taoism, teaching us that finding our own path and following it will make us infinitely more cool and powerful.
Transcendental & great!
(Even if your true path is murder and cannibalism. Less cool for a morale, but still.)
4) Here in Rettousei we have a protagonist, whose only true inborn ability is intercepting any command sequence in existence.
Further applications include: immediate understanding of any magic, even unfinished, disrupting any magic, a need to reinvent usual basic magic spells from scratch every time.
Thus, Tatsuya's main skill
is actually his original soul capability, and he'll probably either evolve it up to Reality Marble (his own subdimension world with its rules), or understand it deep enough for it to rival Great True Magics (which include Resurrection, Creating a Soul, Travelling to Parallel Worlds, Time Travel, Denial of Nothingness, Destruction of Everything and so on.)
Tatsuya is God!