In my opinion the Tedryn Holocron is what really tips it over for Exar Kun, whilst fully studying it is an unlikely prospect, given the vastness of its invaluable content, even just a few hourly sessions behind Vodo's back would be monumentous. Given Kun's statements in Jedi Academy though, he seems to have studied the holocron quite in-depth.
Originally posted by SunRazer👆
I think there's an equally fair argument for Kun/Bane being more knowledgeable. I'd say they're about the same, more or less - it's really a negligible difference and nowhere near as big as the mascots here are suggesting with their waving flags.On one hand, Kun being an actual Sorcerer and Alchemist allows him to divulge all of Nadd's secrets, whereas Bane admitted in RoT that he couldn't understand all of them and instead left some transcriptions for Zannah to study. To that end, we know that Bane's gleaned knowledge about Orbalisks and presumably a bit more, but most of the sorcerous applications explored in Nadd's holocron would be foreign to him. Kun's ability to comprehend all of Nadd's teachings in great detail means that he has the teachings of Sadow and Adas under his belt, since Nadd harnessed knowledge from both. Whatever Nadd failed to obtain from Sadow (if there was anything), Kun picked up as well, so that makes him one of the most knowledgeable Dark Lords already. Bane read some of Sadow's treatises during his time in the Academy, but his sorcerous illiteracy means that he can't comprehend much of Sadow's teachings. It's also worth noting that Bane read a variety of other material in the Academy archives in PoD.
Bane counters by having built up an entire library of Sith artifacts (ie. tomes, holocrons, etc.), including at least Belia Darzu's and Darth Andeddu's holocrons. There's also him having access to the Sorzus Syn holocron as per BoS, and again, whilst he doesn't understand Sorcery and Alchemy in the way Kun does (not to mention Syn's knowledge probably being a more primitive version of Sadow's/Nadd's), it's still a respectable amount of knowledge. We don't know too much about what else he possesses, but we know it's considerable, so suffice to say, this at least equalizes the field, if not puts him in front. Then we have Bane studying Darth Revan's holocron - and though he didn't fully understand everything immediately, he was still capable of utilizing several of the rituals and other techniques (ie. Detoxify Poison, Drain Life) from Revan's holocron, which we know contained knowledge from the Malachor archives, including Zelashiel the Blasphemer or whatever his name was.
That said, Kun is the beneficiary of having trained as a Jedi under Baas, which makes it probable that he studied from the Jedi archives. Above all, though, he reaped the benefits of the sacking of the Ossus library, which would've rewarded him very handsomely with hidden Jedi and Sith knowledge alike. Considering that the Great Library is stated to have contained knowledge from across centuries, it's not hard to consider it the equal of Bane's library or perhaps even its superior in terms of stored knowledge. And as mentioned by others, there's also the Dark Holocron take into account in favor of Kun.
Not seeing a gaping disparity here. Were I to give anybody the edge in terms of knowledge, it'd be Kun, but only because he's an actual Sorcerer and Alchemist. With respects to obtained information, they're roughly equal.