Lily Loud is a recurring character-turned tertiary main protagonist and Zachary's false love interest in the Duo-Franchise. She first ascended in the series as the second Myles Fly. Lily has a crush on Zachary Delightful, the first Myles Fly and later Bladewing. She also teams up with Bluesong, Oceanroyal, Craig Slithers and Achu to fight Grimaulde, and other villains. Lily is also the eldest sister and confidant in the Loud family in the Duo-Franchise although she is not much of a conversationalist. In the arc The End, she is revealed to be one of Zachary's long lost siblings by the name of Stephanie Delightful.
She worked as a maid for the Myles Bots and Zachary Delightful in the time skip between Summer Edition 2 and Conquer the Skies Part 1. However, she realizes her loyalty to Zachary and attempts to earn his affections but things go awry when Zachary's accidents cause an outlawing. Zachary then passes on the Myles Fly name to Lily whilst he dubs himself Bladewing. She then trains herself to become a superhero and fights back against Grimaulde and his monster babies. Unfortunately, she and the Myles Bots were falsely accused and the teens are declared Public Enemy #1. Meanwhile, Achu felt remorseful and joined the Myles Bots when the timing was just right prompting Lily to join the Myles Bots as their ally. Things go awry when she was paralyzed and was promptly rushed to plastic surgery in order to save her life. As the arc progressed, things turned worse and worse until Lori (her little sister and best friend) was abducted and she joins the Myles Bots along with Craig Slithers and a now-revived Bill Cipher. Zachary, Bluesong, Lily, Craig Slithers, Achu and Bill Cipher enter the Yolkians' ship where they encounter Grimaulde and Lisa and Lily avoids the barrels with a hammer and gives it to Zachary as he successfully shots the two off the ship and the villains were banished from the city and the Yolkians leave the planet in peace. Towards the end of the arc, the team are declared heroes and she and Craig began their first kiss as they became a couple. However all this was scrapped though she returns in the final prologue arc The End?, is revealed to be Zachary's faux mother and long-lost sister and during the city's condemnment officially joins the group as an honorary member.