I'll try another. I'm still doing the basic bones of the concept and letting any prospective SG flesh it out a bit.
Miratius of Tytalus does not have a stall. If you do not know who he is, then clearly you are not worth his time. The service he offers is to cast spells which improve characteristics. The cost I suggest is double the vis cost to cast the spell.
Is the cost high for something that literally takes 3 hours? Maybe, however, the PC is not paying for the 3 hours to cast the spell, they are paying for the 20+ years of study to be able to cast these spells.
As Miratius needs to be a CrCo specialist, he can offer healing for a fee if the SG wants to add another string to his bow.
Miratius believes the most important task for any being is to improve themselves. In his own life Miratius has taken this to the extreme. Miratius is physically and mentally close to the pinnacle of what is humanly possible. This has been achieved by an extreme fitness regime, intense study, and multiple Creo Corpus and Creo Mentem spells to complete his quest for perfection.
Miratius looks like the classical sculptures. He is incredibly toned, clean shaven, well groomed, and at most times is shirtless to show off his physique. Miratius is vain and arrogant to the degree he does not think he is better than everyone, he "knows" he is better than everyone. Part of the reason he has healing spells is he will not tolerate being weak. Light wounds, he'll shrug off, and let them heal with assistance from Purification of the Festering Wounds. Anything more is not acceptable.
Miratius will be patronising and critical of anyone asking for his services. If someone disrespects Miratius in any way, he will not cast the spell they want without a grovelling apology. Miratius will not bargain. It doesn't matter if the player rolls a 24 bargain check, Miratius does not bargain!
Miratius is very quick to consider something being disrespectful. For example: If a player questioned the cost, arguing a lower level cheaper vis spell would achieve the same outcome, Miratius would tell them to cast the spell themselves.
As Miratius hates customers so much, why does he sell his services? He needs the vis. His self-improvement, from sourcing the summae and tractatus to improve his Creo, Corpus and Mentem, as well as lab texts for the improement spells, they all cost.
Miratius honestly thinks his customers are pathetic for not improving themselves and won't hide it. He literally despises anyone who in his eyes is weak, no matter the reason. It is this part of his personality which explains why he hasn't improved his communication. He loves being patronising and arrogant, and is concerned his personality will change too much if he magically improves his communication.
He is written to be an eminently unlikable person. Due to his personality, there is a question of who would buy his services? What he is offering is something only a select amount of magi can do, and most who can cast these spells would be a lot older, with a conflicting demand to make longevity potions. His niche service suggests some magi would tolerate him as they really want to buy what he is offering.
I've included some stats, however it's not a full write up as I'll let anyone using him flesh out the last parts. .
Characteristics: Int +5 Per +2 Str +2, Stam +5 Prs +4 Com 0 Dex +1 Qu +2 (Int, Per and Prs improved from +3 since gauntlet)
Age - 45 (can easily have his Age increased, with a commensurate increase in his spell selection, arts and stats. 45 is arguably the minimum age to achieve what is required.)
Essential Virtues/Flaws: Improved Characteristics x 3, Affinity Creo & Corpus. Puissant Creo, Major Magical Focus - improving people. Arrogant/Proud (-3), Restriction (can not be voluntarily holding or wearing magical items).
"only those whose magic is not strong enough depend on props". The restriction is purely psychological, however, he would prefer to die than to be seen to be reliant on a prop.
Traits: Arrogant +3, Vain +3, Driven/Focused +3.
Abilities: Parma Majica 5, Magic Theory 4, Latin 4, Artes Liberales 1, Concentration 1, Finesse 1, Penetration 1, Order of Hermes Lore 1, Native Language (nothing ties Miratius to any cultural group, so choose what works for your story) 5, Athletics 3, Brawl 3, Survival 2, Swim 2.
His abilities are relatively low, apart from Parma, due to his focus on driving up Cr, Co and Me.
Arts: Cr: 20(23) In 6 Mu 6 Pe 6 Re 6 An 6 Aq 6 Au 6 Co 17 He 6 Ig 10 Im 6 Me 12 Te 6 Vi 6.
Essential Spells Known
The enduring mage (lvl 60) Touch range +1 permanent stam increase +5 max, The genius mage lvl 60 int version, The imposing mage lvl 60 presence version.
Pilum of Fire mastery level 2.
Variant Panic of the trembling heart (range sight, target group, duration ring. any rational mage should have a crowd control spell)
Seven League Stride
Purification of the Festering Wound
Incantation of the Body Made Whole
Restoration of the Defiled body.
Miratius could have all of the other +5 max characteristic boost spells or none. For the sake of saving a few vis, he will not learn the lesser versions of the characteristic boost spells (or lesser healing spells for that matter). The season spent learning that spell in not worth the future small vis savings. Long term, it's a smart business move as he can sell his services cheaper, and make the same or more vis, however, Miratius is a reluctant businessman and doesn't consider those things.
Potential interactions with PCs
Buying the spells.
If a SG wants a wizard war, Miratius could easily be baited in to one.
Miratius is all about self reliance, so he won't send the PCs on a task, however, the PCs could hire him. He wouldn't come cheap, however he would be useful.