Short Answer 
In “Miraculous: Tales of Ladybug & Cat Noir,” the main characters, Ladybug (Marinette) and Cat Noir (Adrien), reveal their true identities in the Season 4 finale titled “Kuro Neko” or “Cat Blanc.” This significant revelation is temporary, as the series quickly returns to the dynamics of secrecy, sustaining ongoing suspense.
Step 1: Understanding the Characters
In the animated series Miraculous: Tales of Ladybug & Cat Noir, the main characters are Ladybug and Cat Noir. Their real identities are Marinette and Adrien, respectively. Throughout most of the series, they keep their true selves hidden from each other, leading to exciting moments of mystery and tension.
Step 2: Key Episode Explanation
The pivotal moment where Ladybug and Cat Noir reveal their true identities occurs in the final episode of Season 4, titled “Kuro Neko” (also referred to as “Cat Blanc” in certain regions). In this episode, both characters finally disclose their real names and identities to one another, which is a significant milestone in the series.
Step 3: Importance of the Revelation
Although their identity revelation is a major development, it is crucial to note that this moment is temporary. The relationship dynamics and secrecy regarding their identities return to normal after this episode. This transient nature of their revelation helps maintain the ongoing suspense throughout the series.