He is the son of famous scientist Dr. Yuichiro Hikari, and he strives to be a skilled NetBattler with his NetNavi, MegaMan.EXE.
Lan is quite childish and also reckless. As such, this behavior of his puts him at odds with his rivals. Being reckless easily allows him to takes risks without hesitation. This certainly gives an edge to his Netbattling strategy. Lan is also a sportsman, with a particular love for football and an is excellent inline skater.
He spends a great deal of time with his friends, hanging out with them or eve sometimes pranking them. One of Lan's best friends is his next door neighbor Mayl, whom he has known since their early childhood. Lan is also good friends with Dex, who provides a good source of Netbattling practice as well as providing a sense of humor.
Lan also shares a strong bond with his NetNavi, MegaMan.EXE, who is actually Lan's late twin brother, Hub Hikari. His connection to MegaMan is unrivaled, this allows the duo to preform exceptionally well in Netbattles. MegaMan himself acts as a sort of conscience and voice of reasoning to Lan when his impulsive behavior gets the better of him.
Lan has a strong obsession with food, particularly: curry. Which he will often eat large amounts of if given the choice. He even claims he can out-eat Dex.
Lan has officially gained weight four times, all of which are in the anime.The first time Lan gained weight was in Episode 31: "A Splendid Curry Battle". Durring the end of his world travels, Lan arrives in Namaste and takes part in a All-You-Can-Eat Curry Tour. After quickly eating several of the curry dishes, Lan becomes stuffed to the point of having his jacket bust open.
Lan also briefly gained weight along with Dex and Chisao after gorging on free curry in Episode 54: "Chisao's in Town".
Another time Lan gained weight was in Stream Episode 12: "Jawaii Curry and Tomahawk" during a curry eating contest with a boy named Dingo. Both boys ate until they had emptied the entire pot of curry, causing the contest to end in a tie and both of them to end up with large stomachs. They then engaged in a Netbattle, which also ended in a draw.
Finally, Lan also gained weight in Stream Episode 28: "Pink Punch Meiru". Having eaten so much curry, Lan actually made louder footsteps when he walked.