This was a random idea I came up with. Looking at the counter with Trifaccia, I am not too fond of it. The encounter just seems like filler with some random NPC who the party learns nothing about and are just supposed to defeat. I tend to dislike encounters like that, especially for a scene which is supposed to be as cool as they make it sound.
I was thinking, what if Triaccia is swapped out for Vencarlo, who Ileosa has masquerade as Blackjack? the idea is that, during Scarwall, Vencarlo gets captured by Ileosa's forces when she learns that he is Blackjack (via divination and her intelligence web). Ileosa then has Vencarlo masquerade as Blackjack, making it seem like Blackjack is supporting the crown. Then, instead of encountering Trifaccia, it is dominated Vencarlo instead.
Vencarlo will be buffed to be a suitable encounter, which I was thinking these stats:
Vencarlo Orisini / Blackjack CR 16
Male middle-aged human duelist 8 / swashbuckler (inspired blade) 1 / vigilante 7
CG / CG Medium humanoid (human)
Init: +10; Senses: Perception +19
DEFENSE
AC: 30, touch 21, flat-footed 19 (+6 armor, +8 Dex, +3 dodge, +3 deflection)
hp: 123 (8d10+7d8+55)
Fort: +7, Ref: +20, Will: +7, -5 vs Ileosa
Defensive Abilities: parry, unshakable (+7), Enhanced mobility, Grace, Elaborate defence +2,
OFFENSE
Speed: 30 ft.
Melee: +2 flaming rapier +26/+21/+16 (1d6+17/15-20 plus 1d6 fire) or mwk dagger +24/+19/+14 (1d4+14/19-20)
Ranged: mwk dagger +24/+19 (1d4+14/19-20)
Special Attacks: precise strike +7, startling appearance, Combat reflexes, Riposte
TACTICS
Before Combat: If confronted in his social identity, Vencarlo attempts to flee. If he manages to do so, then Vencarlo switches to his Blackjack identity and confronts the PC’s in a public location
During Combat: If Vencarlo goes first, he readies an action to disarm any PC that gets within his reach. If he disarms the PC, Vencarlo then focuses his attacks on the PC wearing his old Blackjack costume, making use of the time bought. If no PC wears the costume, Vencarlo instead targets the PC he disarmed, attempting to disarm if they pick their weapon up (or draw a new one), parrying as needed to avoid heavy blows. Once he manages to deal with that PC, he moves on to targeting spellcasters or healers. If any PC wields Serithtial, Vencarlo targets that PC above all others, attempting to disarm that PC and grab the weapon.
Morale: Vencarlo fights to the death while under Illeosa’s control, but if Vencarlo is freed from Illeosa’s control, he immediately surrenders to the PC’s. In the unlikely event Vencarlo manages to take Serithtial from the PC’s, he flees combat with the blade and can be found in room A52 with the false Ileosa. Serithtial can be found in room A90 in this case.
STATISTICS
Str: 11, Dex: 26, Con: 16, Int: 14, Wis: 10, Cha: 15
Base Atk: +15; CMB: +15 (+19 disarm); CMD: 33 (35 vs. disarm)
Feats: Dodge, Combat Expertise, Fencing Grace (rapier), Improved Critical (rapier), Improved Disarm, Mobility, Weapon Focus (rapier), Toughness, Critical focus, Bleeding critical
Skills: Acrobatics +29, Bluff +17, Climb +7, Craft (blades) +6, Diplomacy +8 (+12 in social identity), Disguise +10, Escape Artist +16, Intimidate +11, Knowledge (local, nobility) +10, Perception +19, Perform (dance) +7, Sense Motive +20 (+24 in social identity), Sleight of Hand +15, Stealth +24, Swim +7
Languages: Common, Elven, Varisian
SQ: deeds (derring-do, dodging panache, opportune parry and riposte), inspired panache (4), dual identity, exceptional wealth, improved reaction, inspired finesse, seamless guise, social talents (great renown[Old Korvosa], renown, safe house [Vencarlo's home], social grace [Diplomacy, Sense Motive]), vigilante specialization (avenger), vigilante talents (cunning feint, rooftop infiltrator, sure-footed), Acrobatic charge, Dominated, Geas
Gear: +2 flaming rapier, mwk daggers (12), +1 rapier, belt of dex and con +4, bracers of armor +6, ring of protection +3, Slave collar, potion of barkskin +5, potion of heroism, Blackjack costume, noble's outfit, gold signet ring (worth 250 gp)
To me, this would be a more interesting and memorable encounter than one with a random Efreeti, but what do you think? would this work for a replacement encounter, or should I stick with Trifaccia?
I agree that while the idea of another (evil) superhero showing up to try and upstage Blackjack as the city's hero is cool, the efreeti otherwise known as Trifaccia just kind of shows up out of left field with no build-up and is just sort of a big bag of XP for the PCs to break open.
And assuming Vencarlo is still around and hasn't been ingloriously killed off earlier in the campaign or left to rot in the Arkona jail cells because the PCs didn't save him for some reason, it would be good to give him one last bit of screen-time to bookend Blackjack at the end like he was there at the beginning.
However, if I could make one potential suggestion, what about merging what is written with the imposter and your idea to have Vencarlo-as-Blackjack fighting against the party? Specifically, rather than a random nobody efreeti masquerading as some other non-Blackjack superhero, have the "imposter" pretend to be Blackjack specifically - Vencarlo has been sort of retired/out-of-commission since getting captured by the Arkonas, and if a PC has taken up the mantle, they've also been out of the city for a while.
The twist to this "imposter", however, is that it's actually another former Blackjack who has been re-animated, either by Ileosa directly or just as some sort of spiritual blacklash from all the bad stuff that's been happening to the city (including Urgathoa, the Goddess of Undeath herself, poking a finger down at the end of Book Two to revive/transform Andaisin).
So you start with Vencarlo coming to the party, saying that he's heard of some imposter running around pretending to be Blackjack, and he wants to put an end to this before Blackjack's name is permanently ruined in Korvosa. Party investigates, and discovers that it's not actually an imposter, but a real former Blackjack who has come back from the grave but is all mixed up from the experience/being controlled by Ileosa.
You can ratchet up the drama further by making this former Blackjack specifically be Vencarlo's own mentor and predecessor - I don't know if this was someone's addition or a single-line off-hand remark somewhere in the hard cover but I think that person was also Cressidia Kroft's father, so you have another line of drama there (possibly a spiteful attempt by Ileosa here to hurt/throw Kroft and by extension the Resistance off-balance until the PCs get involved).
Season to your table's taste whether this ex-Blackjack can be reasoned with and saved, or has to be laid back to rest as they are simply an undead parody of the person they once were. You can basically use the same stat block you have above for Evil Vencarlo, since this mentor taught him everything he knows. And you can have this interesting little superhero legacy dichotomy with the ex-Blackjack, Vencarlo, and possibly a PC who has taken up the mantle all in the same place at the same time, with some different approaches to how they do things as Blackjack.
So either have a former Blackjack come back (living or undead) or have the Efreeti pretend to be Blackjack?
The Efreeti is fairly self-explanatory, instead of being Trifaccia, he is Blackjack, which still has the shock of 'this guy's actually an Efreeti' while making the encounter make a but more sense, though the Efreeti still seems out of place. Meanwhile the former blackjack might be a bit more complicated, in a sense but fits better than some random Efreeti.
If I am understanding what you said, the former Blackjack sounds like they were animated as an undead or straight up brought back to life, and are somehow being controlled by Ileosa. Then, to add drama, make this former Blackjack be Cressida's father.
I have an idea. I am going to go with the former Blackjack and have them be Vencarlo's mentor, but I am playing into the idea that their resurrection didn't quite go right, Turing them part undead. To represent this, I am going to change the race from human to dhampir.
The lore behind this is that when Urgathoa reanimated Andaisin, that amount of power also spread into the surrounding area briefly. This caused the soul of the prior Blackjack to animate as an undead, but due to how the soul was near the outside of the undead-blast radius, they were not turned into a true undead (they retained all of their class levels). Since then, the former Blackjack has been going around Korvosa, trying to figure out what was going on, only to be captured by Ileosa and dominated. still need to figure out what happens if the former Blackjack is freed.