Leon Loud is the male version of Lily Loud.

1. Appearance - Much like his female self he has light blond hair and usually wears only a diaper most of the time. However, unlike Lily, his hair is shorter and has more teeth. He also doesn't have any eyelashes like his female counterpart.
2. Personality - Despite his young age, he appears to be just as mean as his brothers, as shown in how he bit Lincoln's finger when the boy wanted comfort. However, just like the rest of the brothers in the world with Linka Loud, Leon seems to care a lot about his only sister.

Trivia:

1. Much like their female selves, he, Leif and Lexx are all voiced by Grey Griffin.
2. He is the only brother who does not participate in dogpiling Lynn Sr. and Lincoln. He also doesn't take part in giving the "Loud House-styled" Dutch oven to Lincoln.
3. His Polish name is Henio from Henryk.