Leni L. Loud is one of Lincoln Loud's ten sisters in The Loud House. She is the second-oldest child in the Loud family, at 16 years old, and is the kindest, but also the least intelligent of the eleven siblings. In the spite of her fulfilling the "dumb blonde" stereotype, she makes up for it in beauty and kindness. She also has talents in fashion designing, wood carving, and lock-picking.
Various examples of Leni's simple-mindedness are expressed throughout the series. In "Linc or Swim", she does not know the rules of the game, "Marco Polo", much to Luan's annoyance. In "Project Loud House", she is shown to be unable to walk and chew bubble gum at the same time. In "Changing the Baby", she gets stuck in Lily's crib and thinks that it's a baby prison. When she's being interrogated by Lincoln and Lucy in "Sleuth or Consequences", she thinks they're interviewing her, and states that her favorite color is zebra.
Despite being ditzy and absent-minded, Leni's shown to be skilled at fashion designing, wood carving, singing, lock-picking, and making smoothies, which demonstrates that while she may not be very bright, she is creative and artistically inclined. She is also the kindest and sweetest out of the bunch and gets along well with her siblings.
Leni suffers from arachnophobia, as seen in "Left in the Dark", "No Guts, No Glori" and "Future Tense". This phobia is most prominent in "Along Came a Sister", where Lincoln brings his class's pet spider, Frances, home. When Leni first sees Frances, she panics and attempts to kill her with bug spray. Later on, it is revealed that Frances is still alive, and Dad – who also exhibits arachnophobia – hires an exterminator to dispose of her. Leni faces her fear and cuts off the exterminator, in order to save Lincoln's reputation – once again – showing that she does have a big heart.
Leni has also proved that she can be irresponsible, as shown in the episode "Cover Girls". She agreed to cover for Luna, Luan, Lynn, Lucy, Lola, and Lana, and later passed the task onto Lincoln. However, Leni is shown to be very compassionate, as she was the only one of her siblings to prioritize helping her family get better, as opposed to getting away when the Loud family caught the flu in "One Flu Over the Loud House". In addition, in "No Spoilers", it is shown she is the only person in the family considerate enough in the family to be able to make the perfect surprise party because she pays attention to what people like (excluding the surprise part since she always spoils the surprise because can't keep a secret and is rather ditzy and naive).
Episodes focusing on Leni
- "Driving Miss Hazy"
- "Along Came a Sister"
- "No Spoilers"
- "Shop Girl"
- "Crimes of Fashion"
- "Everybody Loves Leni"
- "Leader of the Rack"