His name is Chiba Mamarou (Darien in the Dub). His childhood was tragic. His parents died in a car accident and he lost his memories, as an Orphan he rose above adversity. He was an ordinary college student when a crumpled up bad test struck him in the head. He insulted the girl who threw it at him. From that day onward Mamarou's life had never been the same. He would constantly run into Usagi and they would exchang jabs, that wasn't it. He'd also experience blackouts. Something deep inside altered hi and he had no idea as what had happened. It later became clear that he was changing into Tuxedo Mask. He was the hero who always assited the sailor soldiers when they battled the Dark Kingdom

One night he experianced a dream from a beautiful princess who claimed to help him know why he was changing into Tuxedo Mask if he found the seven rainbow crystals. He was able to find two of them, but the dark kingdom, his enemy, already had five. They had agreed to meet but he was captured in the ride with Usagi. She surprised him by changing into Sailormoon and he surprised her by changing into Tuxedo Mask. He was injured and everything came into place. The rainbow crystals came together and his memories of his past life returned. He was Prince Endymion and she was princess Serenity.

Sadly after everything had returned he was taken by Queen Beryl and brainwashed into becoming her servant. As Dark Prince Endymion he used black roses to attack the sailor soldiers. He was always at odds with Kunzite/Malachite. Sailormoon temprarily cured him with the cresant wand but Beryl washed away the magic and improved the previous method. Dark Endymion fought against Sailormoon until she pulled out her locket. One touch and he was back to normal. Outrages at the task Beryl killed him.

After the death of Beryl and Metallia the sailor Soldiers and Tuxedo Kamen reowoke in ther civilian forms. Mamrou had no idea Usagi was. A part of him had seperated from his body and became the Moonlight Knight. As the Moonlight Knight he fought the Cardians with white roses and a sabre. During the final battle agaisnt the doom tree he was reunited with Mamarou.

Shortly after the arival of Chibiusa Mamarou recieved a horrible dream that something would happen to Usagi unless he broke up with her. Despite the pain in his heart he broke up with her. He and Usagi reunited when she had seen parts of the dream and they came to the conclusion that no matter what happened the would always be together.

When he journied to the 31st century he discovered he will someday become Neo King Endymion and Chibusa was his and Usagi's future daughter