Mamoru Chiba lives a double life as Tuxedo Mask, secretly embodying the reincarnated Prince Endymion from the ancient Silver Millennium. His name itself forms a pun meaning "Protector of Earth," derived from the kanji in "Chiba" (Earth) and "Mamoru" (to protect). Tragedy struck Mamoru on his sixth birthday when a car accident claimed his parents' lives and left him the sole survivor, suffering retrograde amnesia that wiped his early memories. Haunted by recurring dreams of a mysterious woman urging him to find the Legendary Silver Crystal to reclaim his past, he embraced the mantle of Tuxedo Mask. By night, he dons a black tuxedo, cape with red lining, white mask, top hat, and wields a cane and roses. As a civilian, Mamoru is depicted as a student, sometimes attending Moto-Azabu High School. He lives independently, known for academic excellence and athletic prowess. Initially cold and blunt due to trauma-induced isolation, his character evolves to reveal deep protective instincts and a capacity for self-sacrifice. He possesses psychic abilities: psychometry (reading objects' histories through touch), healing, energy projection, and sensing disturbances affecting Earth. His relationship with Usagi Tsukino (Sailor Moon) is central. They meet antagonistically, with Mamoru mocking Usagi's academics and hairstyle, yet feel an unexplained pull. Their bond is rooted in past lives as Princess Serenity and Prince Endymion—lovers who perished during the Moon Kingdom's fall. After regaining these memories, their romance unfolds amidst external threats. Key developments include temporary separations prompted by prophetic nightmares (engineered by his future self, King Endymion), reconciliations, and eventual engagement. They ultimately marry, becoming king and queen of Crystal Tokyo, and have a daughter, Chibiusa. Mamoru repeatedly faces capture and brainwashing. During the Dark Kingdom arc, recovering his memories leads to brainwashing, forcing him to fight the Sailor Guardians until rescued. In the Black Moon arc, another memory erasure causes a psychic split, birthing the Moonlight Knight persona—an alter ego aiding Sailor Moon until reuniting with Mamoru. The Dream arc reveals a physical link to Earth through his guardian priest, Helios; Mamoru endures a curse manifesting as a black rose in his lung when the Dead Moon Circus corrupts Elysion, the planet's spiritual core. As Tuxedo Mask, he supports the Sailor Guardians in battle, disrupting enemies with thrown roses, projecting energy blasts, shielding allies, and augmenting Sailor Moon's powers. He wields the Golden Crystal, counterpart to the Sailor Crystals, solidifying his role as Earth's guardian. This is pivotal in the Infinity arc, where he channels his life energy to sustain Chibiusa and later awakens the Golden Crystal to help defeat Pharaoh 90. During the Dream arc, he combines the Golden Crystal with Sailor Moon's Silver Crystal to purify Elysion. Mamoru's journey traces a shift from a self-absorbed amnesiac to a selfless protector. His initial desperation for memory recovery softens as safeguarding others, especially Usagi and Chibiusa, becomes paramount. While grappling with insecurities about his role compared to the Sailor Guardians, he consistently proves indispensable in crises, fulfilling his destiny as Earth's guardian.