Unlike the Powder Kegs, Archibald remained part of the Healing Church’s workshop in spite of his own deviancy. The man was merely considered an “eccentric” according to various item descriptions, and this was likely because his inventions weren’t that far removed from the church’s ideals. Rather than aim to create weapons emphasizing flash over usability like his more heretical contemporaries, Archibald kept his creations simple to use even if we assume that they were, mechanically, quite complicated. In this respect, the church could quite easily have incorporated his products into its arsenal. As to what made the man eccentric, he had grown fascinated with the blue lightning enveloping the bodies of darkbeasts, making it his life’s work to recreate them for man’s use. Given that the church workshop arose in the wake of hunters becoming terrible beasts, perhaps Archibald was himself a hunter forced to retire in a wheelchair after witnessing a blood-drunk comrade or more turn into a darkbeast. Whatever the case, there is no denying that he was the only one who came to the workshop with bolts on the mind.
Emblem of a comrade of Archibald, who was known as the eccentric of the Treatment Church Workshop. He issued it arbitrarily.
He who was fascinated with the blue bolts that black-beasts are said to be clad in dedicated his life to their artificial reproduction. In a sense, it was extremely Byrgenwerth-like.
The description to the Spark Hunter Badge notes that his obsession is not at all unlike that of Byrgenwerth, at least so far as lifelong pursuit in mastering the arcane they experienced is concerned. Although an apt comparison, it is odd that such a throwaway line was made for this character when there are so many characters with stronger Byrgenwerth connections. In truth, this is another example of Game Director Hidetaka Miyazaki being meta. Cut dialogue confirms that Archibald had initially been planned to be a researcher of Byrgenwerth obsessed with blood gems, taking any we brought him from the Chalice Dungeon in exchange for upgrading our weapons — and slowly going mad in the process. Even after the character was cut and the name reused, Miyazaki decided to allude to the original concept. That is to say, the text probably isn’t implying that the Archibald referenced in the final game had any history with Byrgenwerth. The two are simply kindred spirits in obsessive pursuits, with the workshop eccentric’s area of interest proving far more straightforward yet less dangerous.
… Who’re you?… Perhaps, a hunter? Oh, then that’s just perfect. My name is Archibald. I’m what you call… a researcher. Of the blood of the gods, and the power of blood. Ah, no need to be so wary. Like you, I’m an outsider, and, well, sane. I simply want to see the truth about Yharnam and beyond it. More importantly, as a hunter, you go down into the gods’ graves, yes? In that case, bring me the gods’ blood, blood crystals. I think I can empower you with them…
Heheh… unbearable, isn’t it…? I’m well aware that Byrgenwerth’s gone mad… Even I seem to be losing my head…… Here, this is yours. Isn’t it wonderful? But, take care not to go blood-mad…
You have them… Don’t you have blood crystals? Heheh… smells like it… Hurry and give them… hurry…
Heheh… you smell… It’s so rich… (exaggerated lip-licking)… Can’t you already taste them…? Hey, hurry, hurry and give them…!
In the end, Archibald succeeded in replicating beast lightning’s effects, formulating special paper to clad weapons in bolts through friction much like Fire Paper. Once the method was devised, he incorporated it into the invention of electric weaponry, namely the Tonitrus and its smaller counterpart. While the English description labels them both morning stars, they are quite clearly closer to regular maces; the Japanese text likewise only calls them iron ball hammers. Regardless, the Tonitrus manages to generate bolts around the iron ball through rubbing like Bolt Paper, the Tiny Tonitrus additionally making use of Quicksilver Bullets to launch those bolts across the ground. It is this function as a blood catalyst and strength of the lightning for the admittedly heavy cost which makes it Archibald’s masterpiece, not that it is “like” his masterpiece as the localization purports. Put another way, Archibald achieved his objective: man now has the same power as darkbeasts.

Unique “trick weapon” produced by Archibald, who was known as the eccentric at the Treatment Church workshop.
Artificially reproduces the blue bolts that black-beasts are considered to be clad in by rubbing this odd iron-balled hammer like a match.
However, it seems that the hunters of those days didn’t like it very much……
Unique “trick weapon” tonitrus produced by Archibald, who was known as the eccentric at the Treatment Church workshop.
This is that same type of odd iron ball hammer and makes Quicksilver Bullets the catalyst. Sticks into the ground and artificially reproduces the blue bolts that black-beasts are said to be clad in.
The catalyst’s efficacy is high and its bolts strong. That is the grounds to consider it Archibald’s masterpiece.
Unfortunately for Archibald, his masterpiece wasn’t very popular. Almost no one adopted the eccentric’s weapons, a stark contrast from the niche popularity of the Powder Kegs. This isn’t due to a lack of literal firepower, since hunters did like using the Bolt Paper. Rather, this was most likely because the Tonitrus requires proficiency in the arcane to make the most of the lightning. The bulk of hunters aren’t in tune with the eldritch mysteries, and the lack of a sharp edge meant that the electric hammers couldn’t suit their physical strengths either — why invest in a Tonitrus when a saw cleaver or whirligig saw can perform just as well without the additional effort? Beast hunting simply doesn’t attract the kinds of people liable to benefit from Archibald’s discoveries, which obviously wasn’t what he expected. In fact, this failure to be recognized for his undeniable achievements is likely the reason for him issuing his own, admittedly crude, hunter badge identifying “friends” to his work — his ego had to take what it could get. The church might have been alarmed by this if there were more than a handful of takers.

Specially-made paper that clads weapon in bolts by rubbing this on.
It is an invention of Archibald, who was known as the eccentric of the Treatment Church workshop, and artificially reproduces the blue bolts that black-beasts are considered to be clad in.
It is said that, unlike the odd weapons produced by him, there were hunters who liked this. Especially if they had seen a black-beast even once.
When all is said and done, we only see Yahar’gul hunters counted among Archibald’s followers — assuming that he is still alive, it is possible that the eccentric himself is secretly a member. Given his proximity to the hole in the Hypogean Gaol, these bolt hunters may have included Paarl. However, this heretical cleric ultimately suffered the scourge regardless, becoming the massive darkbeast slain and left to rot in a sealed corner of Old Yharnam — fitting that his name means “pearl”, a gem known for its bluish white color. Considering how few darkbeasts are encountered outside the Chalice Dungeons, Paarl’s use of bolt weapons likely contributed to his unique degeneration. In that case, it is probably for the best that more didn’t earn Archibald’s badge.