Why did Kuzan join the Blackbeard Pirates?

We know Kuzan hasn’t all of a sudden turned evil, we are told as much in his conversation with Smoker.

When they are all drinking at the bar, Catarina Devon suggests Kuzan might have information about the missing Red Poneglyph. Laffitte shares some intel about the “man marked by flames” and Shiryu mentions it might be in the hands of the World Government.

None of the Blackbeard Pirates crew mention Ohara. However, the next panel Kuzan connects the conversation to Ohara and Jaguar D. Saul.

At first he immediately refused to join the Blackbeard Pirates, but given some time he reconsidered. Clearly he thinks he can use the Blackbeard Pirates to achieve his goal.

His goal likely traces back to Ohara and Jaguar D. Saul. Kuzan had long been tormented by internal conflict and awaited Robin’s answer.

The events at Enies Lobby finally provided the answer he sought.

His internal conflict has been resolved, the lazy justice gone, he’s now a determined man on a mission.

Realizing that the Blackbeards are trouble, he ultimately decided to adopt Smoker’s approach and infiltrated the crew, like Robin used to do.

“Why are you telling me this?” or in other translations, “what do I have to do with this?” explicitly connects Kuzan with them. He has already been influenced by Luffy and is highly likely to be connected to Dragon in the future, if not already.

Although this line may initially come across as cold, its underlying meaning is quite the opposite. Kuzan recognizes that Luffy and Dragon are only perceived as enemies of Garp at a surface level. Garp himself doesn’t adhere to the World Government’s Absolute Justice and instead follows his own set of values, which align with those of Luffy and Dragon.

This is evident through various instances, such as Garp rejecting promotions, showing disdain towards the celestial dragons, being chosen by Roger to raise Ace instead of Whitebeard or Rayleigh, and entrusting the upbringing of Ace and Luffy to a mountain bandit.

Kuzan knows Garp. The implication is that Kuzan too is only an enemy at surface level.

A former admiral, turned pirate. Taking different perspectives of the world. The other major organization left for him to join is the Revolutionary Army. Which not only ties him to Dragon, but also to Ohara.

Regarding the Blackbeard Pirates… Be wary, Titanic Captains, a dangerous iceberg lurks nearby.

Theory by Suntsuo (https://www.reddit.com/user/Suntsuo)