Tohsaka Rin - As Second Owner of the spiritual land of Fuyuki, Tohsaka Rin is nominally responsible for overseeing the activities of all magi and managing the other supernatural goings ons of the city, though realistically, the authority of her position is held only in name (especially given the actions of her "teacher" Kotomine Kirei and the ancient magus Matou Zouken). An Average One and an advanced practitioner of Jewel Thaumaturgy (possessing 20 A-rank Jewels), helped by the Tohsaka sorcery trait of
Transfer of Prana (especially into vessels), she is nonetheless troubled by the presence of Yumizuka Satsuki, whose prana leakage is of a scale that her raw ability is probably on par with a DAA.
Sajyou Ayaka - Believed by most to be a mundane with insight into the supernatural (a "faction leader" in this regard),
Sajyou Ayaka (a literal classmate of Rin) is a quiet, rather solitary individual who prefers to observe the world rather than be part of it, though she will join in if she feels the need. Notably, her nature as a magus - and as a Puella Magi - is unknown to the Second Owner, who believes her to be a mundane. This is to Ayaka's liking, as she uses her position as the head of the Occult Club at Homurabara Gakuen to hide in plain sight, ironically vanishing from Rin's threat radar as she surrounds herself with various witchcraft and occult-related paraphernalia (that she happens to be skilled in future prediction via tarot or other forms of divination, as well as a medium of sorts is just a bonus). Saegusa Yukika describes her as having a similar "distant air" as Tohsaka Rin, though she is not in Rin's league as far as sports or such. Still, she can be competitive when asked, having won a bread eating contest, and participated in a sports tournament at Mitsuzuri's request, among other things. Chief among her hobbies is raising and picking mountain herbs and wild flowers for potions....
Yumizuka Satsuki - Nominal leader of the Puella Magi in Fuyuki, and in raw magical strength, the most powerful wielder of magecraft in the city, Yumizuka Satsuki is considered by most magi to be an enigma wrapped up in a riddle wrapped in mystery. Investigations into her background have turned up no evidence of a supernatural bloodline, with all indications pointing to the fact that until a number of years ago, she was just a shy girl with an inferiority complex (albeit an honor student in school) - which Matou Zouken believes to be an absurd fabrication. After all, he once laid an ambush for the girl by seeding a park with a pack of his worm familiars, thinking she would prove easy prey, only for the Puella Magi to destroy them with the expansion of something like a Reality Marble.
Matou Zouken (NPC) - One of the magi who originally founded the Grail War, Matou Zouken is a shrewd and powerful, if ancient, magus, who serves as the patriarch of the Matou family and has an obsession with immortality, using methods comparable to vampirism (or lichcraft) to expand his lifespan, putting the majority of his soul into one of his worm familiars, projecting a small portion into the "bodies" he displays as mere puppets of the soul (which he considers disposable, needing to be changed every so often). He became concerned and intrigued several years ago, when he detected the prana pulse from the contracting of Sacchin, as the presence of a magus of that level of ability could threaten his plans. However, as time went on and there was no intervention by this mysterious girl, he began to think that she was perhaps simply an anomaly with a great number of magic circuits - one who would be ideal for use as a puppet. Thus, he laid a trap for the girl, seeing a park with a pack of his worm familiars, in such numbers that even a skilled magus would be overwhelmed. One way or another, he'd determine the truth - though he had not expected the girl to simply ignore the damage to her body, somehow
negating the corrosive effects of the worms and expanding a
Reality Marble.
...since then, he has become quite uneasy, and has "suggested" to Shinji that he try to romance Sacchin, in the belief that it would be easier to trick a teenage girl (if that is what she truly is) and trap her with subterfuge, than it would be to directly confront her, as he views her as both threat and opportunity.