Crocodile was one of the first major villains to ever appear in One Piece. Although his first appearance depicted him attempting to take over Alabasta, later appearances revealed his past connections with Emporio Ivankov.
Although being acquainted with Emporio Ivankov didn't become a large factor in Crocodile's identity, Ivankov supposedly knew a crucial secret of his that sparked many theories.
While Crocodile secretly being Luffy's mother is a rather odd theory that still maintains its presence within the fandom, it is possible that Crocodile could have been an officer of the Revolutionary Army. His departure from the organization could be his biggest secret.
Disclaimer: This article contains spoilers for One Piece and is a speculative theory that reflects the writer's opinion.
One Piece: Crocodile secret might've been related to his actual goal altogether

Crocodile has been among the most calculated and competent villains ever introduced throughout the series. While many of the recent villains completely outclass Crocodile in combat prowess, his overall character relies on calculated measures and plans to achieve his goal.
In essence, Crocodile has created an image around himself as a rather cunning, ruthless, yet highly capable leader akin to Doflamingo. Given that Crocodile's secret apparently holds the capability to pacify him completely, many expected the secret to be that Crocodile was once a woman transformed into a man by Emporio Ivankov's Devil Fruit powers.
Although that secret seems fairly major, it is important to note that Crocodile's overall image as a competent leader or his notoriety will not be hampered if he was revealed to be a woman transformed via Ivankov's Devil Fruit.
Crocodile's secret may greatly impact his image and reputation as a leader, leading to his pacification at the slightest threat via Ivankov. Given that Ivankov is one of the highest-ranking Revolutionary Army officers and mostly spent his time conducting various missions, Crocodile's secret might be related to the army itself.
Crocodile's overall goal of taking over Alabasta was simply a ploy to overthrow the World Government. While Alabasta seems disconnected from the World Government, it still remains one of its subsidiaries. Given that Crocodile's motives align with those of the Revolutionary Army, he might have become a part of the army, especially given the army's rich history of working with the Warlords.

Crocodile's time within the Revolutionary Army must have led to the meeting between him and Ivankov, which eventually might have led to Crocodile's falling out with the army. Crocodile must have failed an integral mission on very unfavorable terms.
His goal of overthrowing the government instead of uprooting it like the Revolutionary Army could have led to his departure from the organization, with his critical mission failure being the last straw. Given that Crocodile is currently highly respected by pirates due to his actual skills and competent nature, his critical mission failure from the past with the Revolutionary Army must be his so-called secret held by Ivankov.
Final thoughts
One Piece chapter 1143 will be released on March 23, 2025, focusing mainly on the giants’ counterattack against the God Knights' assault. Although Crocodile has made numerous appearances throughout the series, he hasn't taken any major steps in the recent chapter, only appearing as part of the Cross Guild alongside Buggy and Mihawk.
Related links:
- Gunko's actions in latest One Piece spoilers all but confirm Oda's Germanic inspiration
- One Piece Chapter 1142: Loki sets Elbaph ablaze as the Holy Knights make their move
- The Lodestar Island is just as important in One Piece as Laugh Tale
- This One Piece character's presence in Elbaph may be related to the new Holy Knights