Lee Sin/Background

Lore: The blind monk of Ionia
The Ionian vs Noxus match started due to a monk in the Ionian Lotus Garden setting himself on fire in protest of the Noxian occupation (JoJ, Vol 1 issue 7). The monk did not allow his fellow monks to set the fire off until Ionia was free from Noxus. Two months later, when Ionian won the match for its freedom, the monk allowed for the fire to be put off. The monk "had suffered the loss of his eyes, along with other severe injuries from the intense heat" (JoJ, Vol 1 Issue 12).

Story
As a young teen, Lee Sin was intent on becoming a summoner. His will and dedication were unmatched by any of his peers, and his skill drew the attention of Reginald Ashram, the League’s High Councilor at the time. While studying at the Arcanum Majoris, Lee Sin became frustrated with instruction paced for the other students. He spent his free time researching the nuances of summoning in hopes of graduating sooner. He made amazing advances in his arcane studies, surpassing all other students. By all indications, he would have become one of the League’s greatest summoners were it not for one terrible mistake. Too impatient, he attempted to test his ability by summoning a beast from the Plague Jungles. What he summoned instead was a young boy, but not in one piece. He barely had time to look the boy in what was once his face before the jumbled human mass fell lifeless to the floor. A League investigation later revealed that the boy’s entire village was obliterated by feedback from the ritual.

Lee Sin’s talents were so promising that the League was willing to overlook the incident, but he could never forgive himself. He left the Institute and journeyed to the Shojin Monastery for eternal repentance, swearing never to practice magic again. Years later, hoping to atone for his crime with martyrdom, he set himself ablaze as a protest of the Noxian occupation of Ionia. He remained alive in this state, enduring searing agony for weeks. His actions paved the way for a League match wherein Ionia prevailed, but by the time he was doused, his eyes had been burned completely from their sockets. Hailed as a savior, he was reborn, and his will to act invigorated. He joined the League of Legends to continue his atonement with sweat and blood, a true monk’s only possessions.

"The actions of one may sunder the world, but the diligence of many may rebuild it." -

Development
He was from the first 6 champions developed. Hohums has confirmed that the Blind Monk and Udyr have no relation. Guinsoo revealed Blind Monk's true name: Lee Sin Blind Monk's model was used in WCG for the spectator.

His height is similar to that of Jax, basing upon his concept art.

It was said that he was remade into Udyr The Animal Spirit. However, Riot Game Designer Guinsoo hints that this is not the case.

It has been strongly implied that he was the burning monk during the Ionia/Noxus feud, in Issue 12 of the JoJ, stating "His brethren hastened the monk’s blistered body swiftly back to the monastery for treatment. While it was clear that he would survive, the monk had suffered the loss of his eyes, along with other severe injuries from the intense heat." These would seem to corroborate the "Mystic Meditation" icon, as well as the fact that flickers of flame can be seen in its portrait.

If this is true, it could be that Lee Sin is a reference to a real life monk who burned himself as act of protest against the persecution of Buddhist monks during the Buddhist crisis in South Vietnam.

Ezreal has stated that the blind monk has been deconfirmed.

In Maokai's Art Spotlight, towards the end a tab is shown titled "blindmonk.psd", which could mean that artwork is being done for Lee Sin, that the Rioter's are trying to tease the Blind-Monk fanboys or that the artist in question just likes working on Blind monk for fun.

Also, in the video "Brolaf, the King of Bromacia" the name `Blind Monk` can be seen on the New Champions Board Here. This however was most likely done as a joke by the staff as in the same list there are other champions Riot has long stated to have ceased development.

Champion Sneak Peek: Lee Sin, the Blind Monk
Announcement made by ByronicHero on 22th March 2011 :

Last year, around this time, we were forced to say our goodbyes to a loved and cherished friend, taken from us so tragically and so senselessly before his time. On April 1st 2010, we bid farewell to Urf the Manatee. It was a trying time for all of us all, and many came forward to pour their hearts out and memorialize this noble prince among Sea Cows.

If there’s anything that the death of Urf the Manatee has taught us, it’s that people deal with grief in different ways. For instance, take this gentleman here. Lee Sin was so shaken up that he actually ran off and joined a monastery. Now he’s Lee Sin the Blind Monk. Hey, what do you mean you’ve seen him before?

On March 23rd an Art Spotlight featuring him was added to the Youtube channel of Riot showing the possible final concept art of the character.