This Bonisagus concept mutated a bit during creation - the original idea was a "dabbler" who tried to standardise new spell parameters, but I ran into the problem that I had to decide what actual magic to give them and somehow ended up with Muto Ignem and an overly complicated approach to bypassing magic resistance.
Characteristics: Int +4, Per +1, Pre -1 Com -1 Str -1, Sta 0, Dex 0 Qik +2
Size: 0
Age: 25
Decrepitude: 0
Warping Score: 0 (0)
Confidence Score: 1 (3)
Virtues and Flaws: The Gift; Hermetic Magus; Flexible Formulaic Magic, Greater Immunity: Fire; Great Intelligence, Inventive Genius, Puissant Magic Theory*, Puissant Muto, Secondary Insight; Magic Addiction, Tormenting Master; Carefree, Deleterious Circumstances (when cold), Disfigured, Weird Magic
Personality Traits: Enjoys playing with fire +3, Cheerful +3, Ambitious -1
Reputations: None
Combat:
Dodging:
Soak: 0
Fatigue Penalties: OK, 0, -1, -3, -5, Unconscious
Wound Penalties: -1 (1-5), -3 (6-10), -5 (11-15), Incapacitated (16-20)
Abilities: [Area] Lore 1 (legends), Artes Liberales 1 (spontaneous magic), Athletics 2 (running), Awareness 2 (fires), Brawl 1 (dodge), Charm 1 (magi), Code of Hermes 1 (Bonisagus clauses), Concentration 4 (Magic Addiction), Folk Ken 1 (magi), Guile 2 (excuses), Latin 4 (Hermetic terms), Magic Theory 4+2 (non-standard spell parameters, Native Language 5 (expansive vocabulary), Order of Hermes Lore 1 (Bonisagus), Parma Magica 1 (Aquam), Penetration 1 (Ignem)
Arts: Cr 5, In 1, Mu 10+3, Pe 1, Re 0, An 0, Aq 0, Au 0, Co 0, He 2, Ig 5, Im 0, Me 0, Te 5, Vi 5
Twilight scars: None
Equipment: Wizardly robes, somewhat charred
Encumbrance: 0 (0)
Spells known:
Doublet of Impenetrable Silk (MuAn 15) +13
Wall of Thorns (CrHe 20) +7
Palm of Flame (CrIg 5) +10
Show of the Flames and Smoke (MuIg 10) +18
Prison of Flames (MuIg 20) +18
Trapping the Fire (MuIg(Te) 25) +18
Wielding the Invisible Sling (ReTe 10) +5
Unravelling the Fabric of Ignem (PeVi 15) +6
Character Notes
This Bonisagus loves playing with magic - changing it, playing with it, feeling its power run through them. They don't really have any major research projects planned currently, but are toying with the idea of inventing some new spell parameters - new ranges, targets or durations to use with their magic. Their parens thinks they're not being nearly ambitious enough. Then again, their parens has never forgiven them for giving the orthodox answer rather than their parens' pet theory in their gauntlet Magic Theory exam - despite the fact that their project to break one of the limits of magic continues not to bear much fruit.
Yet their parens' occasional attempts at meddling, magical over-indulgances and even the scars from an incident when they were a child that left them covered in burns seem to have had little effect on the mind of the Bonisagus - they remain blissfully concerned by the vageries of life. They came out of the "incident" with a strange immunity to any future fires, and at some level expect the rest of life to treat them in the same way.
Customisation Notes
The basic idea of a magus who tries to create new spell parameters does not require any specific Art combinations, so those and their spells could be changed. Flexible Formulaic Magic is useful to give the character's spells greater range or duration - without it the character will need to be careful how they transport the stones "Trapping the Fire" creates. Greater Immunity to Fire could be dropped, but if you do that whilst keeping the Ignem spells you are likely to want to add Ward Against Heat and Flames.