- He is the only character that cannot max out all of his skills, as each of his skills have six levels and the max character level is 18 (18 points for a total of 24 possible ranks).
- However, in the Ultra Rapid Fire (2015) featured mode, there is no limit to a champion's level, so Udyr is able to have 6 levels for his abilities.
- He is one of the few characters without an ultimate along with . Udyr has 4 skills that can be leveled up to the maximum rank of 6.
- Udyr is one of a few champions to have multiple textures in one skin. Udyr however has more different textures in one skin than any other champion, as he has a different one for each of his stances.
- Udyr's dance references the Drunken Master Kung Fu Style.
- A side-by-side comparison can be seen here.
- Udyr is one of two champions that went into the weekly champion rotation on the day of their release. The other one is .
- Udyr was one of the champions chosen for the Ionian pool available during the Ionia vs. Noxus match. He was one of the selected champions, and was voted the MVP.
- Udyr is voiced by J.S. Gilbert.
- Udyr was designed by Steven 'Coronach' DeRose.
- He was the first Champion released after the official October 27, 2009 launch of the game.
- Udyr's original champion title was "the Animal Spirit" but with the Freljord patch his champion title was changed to "the Spirit Walker" and changes were also made to his lore.
- His name Udyr literally translates into 'Beast~Monster' in Danish, Norwegian Bokmål, and Nynorsk (cognates: Swedish odjur, German Untier, & hypothetical English *undeer),
- all from negative prefix *un- & nominal base *deuzan ("wild animal", narrowing down to in English) .
- However, udyr is mostly used to describe people acting like animals, i.e. instinctively.
- Almost all of Udyr's skills are based off the , with the sole exception of the Azure Dragon.
- Udyr has 4 unreleased icons for his basic abilities:
- Being a Spirit Walker, Udyr can harness a small portion of power of a dozen Great Spirit animals such as
, , , , , , , and more.
- and represent the Great Bear and Ram respectively. As such Udyr can harness a small portion of their powers.
- Part of his power possibly comes from his diluted vastayan heritage. 
- "If Peta asks, this fur is fake." refers to the Animal Rights group and their notorious ways of getting the public to not wear fur.
- The scene depicted has him using .
- This skin shares the Day Job theme with:
- He wears a , which denotes high competence in a martial art.
- The splash art suggests he is in his .
- This skin again references the , like Udyr's classic, albeit the is antlered, probably paying homage to the .
- The theme behind Udyr's Ultimate skin is one of the possible outcomes for Runeterra. In this future, Udyr reaches inner harmony and conquers his rage during his time with the Ionian monks. He then guards the Hirana Monastery from demons and corrupt monsters that would use the Temples power for the destruction of Runeterra.
- This future may also depict a possible outcome for .
- His appearance and clothing style parody Japanese monks' appearance, with comically oversized & worn , , , samurai's , & stylized non-Japanese , yet without the robe.
- He also bears a striking resemblance to the Sura Master NPC from Ragnarok Online, if one doesn't count for the hairstyle.
- Spirit Guard Udyr's Level 5 has a similarity to the Street Fighter character , one of alternate forms. Both have bluish glowing skin and aura, a large prayer beads, bear-claw shaped hands, exposed upper bodies and gruffy hairstyle resembling flames.
- Using a Dance, Laugh, or Taunt emote command with Spirit Guard Udyr summons whichever spirit corresponds to his current stance. His Dance will summon all four spirits in sequence once any given ability has reached rank five. His Joke summons , which finally explains where Urf's spirit went after being killed by .
- This skin represents his state as a monk after finding his inner harmony and conquering his rage completely, even when fusing with one of the four spirits. This stands in strong contrast to his non-ultimate skins which represent his feral nature and somewhat still-uncontrolled rage.
- This skin shares the Definitely Not theme with:
- It also shares the 'Disguise' theme with:
- He is taking a group .
while striking a pose, but his can't detect
- got locked out of his own party.
- He was released in celebration of April Fools' Day 2015 along with:
- His Usain Bolt's Signature "Lighting Bolt" Celebration Pose. animation is probably a reference to
- He switches between a , , and for each stance.
- This skin shares the Dragon World theme with:
- can be seen in the background of his splash art.
- This is Udyr's first skin to have a new run animation outside of .
- Udyr serves as the shaman for the Winter's Claw and is
- He is speculated to be the man for whom Sejuani's mother Kalkia abandonned her tribe.
- Udyr and formed a friendship after the latter traveled to the Freljord to learn more about spirits. He traveled with Lee Sin back to Ionia in order to learn more about spirits and aided in defending the Hirana monastery from Noxian invaders.
- Despite harnessing the power of the Great Spirit of the Bear, Udyr does not trust . He respects his brother , the Great Spirit of the Ram, far more.
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