Bloodborne, being heavily inspired by H.P. Lovecraft's work, is a game about intelligence. Many of its named characters either seek higher knowledge or have been driven insane by it, and the contents of this list are no exception. The player is encouraged to gather Insight throughout the game for important purchases or just for weird background changes.
It can't be said how much Insight these characters have, but it's clear that they're some of the smarter characters present in the game, despite the questionable decisions many of them had made throughout their lives.
10 Provost Willem
Starting with one of the game's most intelligent characters, Willem was the head of Byrgenwerth, a prestigious school that taught characters such as Laurence, Micolash, and Caryll. Known as "Master Willem" to some, he was fascinated by the eldritch and sought to elevate his own mind. Among other pursuits, he sent expeditions under the labyrinths under Yharnam, to learn about the Pthumerians, an ancient race who were said to have truly understood the eldritch. Players will know these labyrinths as the chalice dungeons and maybe spent a little too much time in there.
He was ultimately left to his devices in Byrgenwerth, eventually making contact with the Great Ones through Rom, the Vacuous Spider. Before Laurence had left Byrgenwerth to found the Healing Church, he told him to "fear the old blood." Despite being ignored by Laurence, he was ultimately correct, predicting Yharnam's fall before it began.
9 Runesmith Caryll
A student of Willem's, and one only known to the player through her work: Caryll Runes. While she (probably) didn't create every rune the player encounters, she was the first to create them, transcribing the whispers of Great Ones into runes that captured their very meanings. Due to this unique skill, drawing power without relying on the old blood, she was highly revered in Byrgenwerth and likely Yharnam as a whole.
Caryll might not be a "she", but it is traditionally a female name. Unfortunately, there is very little lore regarding runesmiths or their work in Bloodborne. Perhaps someday.
8 Micolash, Host Of The Nightmare
Despite initial appearances, Micolash is an extremely intelligent character and one of the most important figures in the lore. He was a student of Willem's, later joining the School of Mensis in hopes to commune with the Great Ones. Willem succeeded in this, with one of his students, Rom, achieving Kinhood through Kos. Micolash and a group of other Mensis scholars attempted the same in a dark ritual, using Mergo as bait to beckon the moon and, thus, the Great Ones.
The ritual worked somewhat, but Micolash was driven insane, leaving the player to kill him and silence Mergo's cries, thereby stopping the Great Ones from intruding into the dream. Ultimately, Micolash wanted humanity to ascend into a greater plane of knowledge – to be granted "eyes." By his dialogue, he apparently succeeded, at least for himself.
7 Archibald
In an effort to lessen public fear of hunters' potential beasthood, the Healing Church banned beast-related studies. One person affected by this was Archibald, an eccentric inventor fascinated by the lightning emitted by darkbeasts, who could no longer access the subjects of his study. To get around this, he secretly worked with the School of Mensis, who provided him a place to study in Yahar'gul, Unseen Village, in return for his inventions. Having said that, Archibald is never shown in-game, so the image is Darkbeast Paarl, whom he likely studied. As funny as it would be, Paarl is not an eccentric inventor of the Hunter's Workshop.
Anyway, while ahead of his time for some, Archibald's inventions like the Tonitrus and Bolt Paper were prized by Yahar'gul hunters. They were especially useful for combating the Kin-using Choir, given their weakness to lightning. While no provost, Archibald was a brilliant inventor and, similar to Caryll, found power without relying on the old blood – a rare quality.
6 Moon Presence
While putting a Great One on this list almost certainly cheating, Moon Presence still warrants a mention. The manifestation of the dream is due to the Moon Presence, and most of the player's and Gehrman's actions are fated by it. It set many of the game's events in motion in an attempt to reach their son, Mergo, and to allow the dream to end.
It shouldn't need explaining how a Great One holds unfathomable knowledge, as that's practically the theme of Lovecraftian horror. For that matter, Kos and the other Great Ones can be considered honorary members of this list, as far as intelligence goes.
5 Retired Hunter Djura
A veteran hunter whom the player meets in Old Yharnam, which was long since burned to quell the growing beast threat. Djura was a member of the Powder Kegs, a "heretical" group of hunters who specialized in explosive weaponry. Fans of the Cannon, Stake Driver or even the humble Rifle Spear have them to thank. While it's not known what happened to the Powder Kegs, Djura is the last known one, wracked with guilt and defending Old Yharnam's beasts from the player.
It's doubtless that Djura would have had some say in the invention of such complex weaponry, saying something about his intelligence. He also renounced his vows as a hunter, aware enough of the dangers the blood brought to stay out of it, and while he's described as "foolish," hanging out in a clock tower with a gatling gun sounds pretty good compared to dying a hundred times.
4 Annalise, Queen Of The Vilebloods
The only remaining member of the Cainhurst Vilebloods, hidden behind an illusion and protected by Martyr Logarius. She survived the Executioners' purge and continues to pull the strings through the player, should they choose, or potentially others. It should be assumed that a noble, especially given her eloquence, is well-educated.
Simply put, Annalise is here for two reasons: there's a surprising lack of notably intelligent characters in Bloodborne as most are religious fanatics, and being sane and healthy by the end of Bloodborne is an achievement in itself. She also knows not to marry someone she just met, which is a bonus.
3 Doctor Alfredius
For those unaware, Titan Comics released a series of Bloodborne comics, including one named Bloodborne: The Healing Thirst. The Healing Thirst followed Alfredius' investigation into the Ashen Blood, a sickness that consumed most of Old Yharnam and later led to its destruction. With the help of Priest Clement, a member of the Healing Church, they discovered the origin of the Ashen Blood to their own peril.
Given that intelligence usually leads to death or becoming a Great One, simply being a doctor-physician makes Alfredius a contender for this list. However, his discovery of the Ashen Blood's source, assisted as he was, answers questions unaddressed in the game, as well as gives more context towards the corruption of the Healing Church.
2 Gerhman, The First Hunter
As one would expect from the name, Gehrman was the first to hunt the beasts of Yharnam. To do this, he modified his clothes to better protect himself and created the Burial Blade – the first of many trick weapons. He is responsible for sending the player on their way, as well as likely training countless other hunters during his time in the dream, potentially including Ludwig. While he was retired to a wheelchair, likely due to his lost leg, he still offers the player advice and ways to better themselves as a hunter of beasts.
He is also just as powerful an enemy as he is an ally, standing as one of the game's final bosses. He also uses the Art of Quickening, a technique used by the Old Hunters that long since fell out of use, save for Gehrman and Lady Maria. He has much to offer the player, such as advice or the workshop, though he was a little too generous with the boss fight.
1 Laurence, The First Vicar
To be clear, Laurence is not a wise character. Intelligent, yes, but blatantly ignoring Willem's warnings wasn't his brightest moment. He left to find power in the old blood, despite said warnings and founded the School of Mensis to assist humanity through the Great Ones. Soon after, he and the school founded the Healing Church, which introduced blood healing and transfusion.
The introduction of blood healing was what caused the issue of beasts in Yharnam, but it's not all Laurence's fault. As far as symptoms go, turning the patient into an unspeakable beast isn't a common one, even if Willem specifically told him to fear the old blood.
Bloodborne is available on PlayStation 4.