Then throw in the Golden Apple of Eris Discordia (aka "GM dice") and let things rip.
I suspect that you will actually need a little more background
informations for this, like for example about Lord Muthermere
(and his guards, since one of the characters wants to murder
him), about Sir Peter, about Sir Peter's potential patrons, and
of course about the location where all is to take place.
In episodic stories, you only need the bare basics of the characters involved at first. As stories develop and they become recurrent, then
you can apply the layers - or take the layers off like opening up a Matryoshka. You choose a name, a title, give them a description and a word about their nature maybe- old boot (grouch, curmudgeon, miser); young male social dilettante who's squandering his inheritance before his father's dead (vacuous, capricious, bit entitled, posh oik); canny man with more money than God who'll want to know what's in it for him before he commits so much as a brass farthing (scheming, pusillanimous, greedy - but generous if the rewards outweigh the risks).
It'd be good not to get attached to a recurring character, either, always bearing in mind what JMS used to do: give each character a ripcord to allow them an exit from the campaign. That way, one can keep one's list of NPCs moving, keep them fresh, make sure the characters don't rely on the recurring characters too much.
Besides, don't you draw up dozens of NPCs anyway, just to fight them? If you want to pit guards against the PC with a sword, use a character whose stats you've already used in a previous adventure. Guard 3 from the Affair of the Governor's Daughter can be dusted off and used as Courtier Four, who brings the bad news to the court about a skirmish that has erupted on the border, that could lead to war, in The Affair Of The Crimson Stranger this week.