Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This build along with this rune set makes Udyr a bonegrinder. Really, good Udyr does not need attackspeed runes, hp runes or other silly toys. REAL Udyr smashes into 4 guys, kill two and runs cuz Udyr need to take a leak. Led Udyr explain.
Runes - why DPS runes for quasi-tank champ? Because when Udyr uses tiger stance, tiger stance bleed applies crit dmg on it. It mean that if Udyr attack critically for 400(impaler is not applied into dmg on mobafire, which is strange) Udyr will make Udyr's opponent bleed for 1200 dmg in 2s. And this is useful when attacking with bear stance too.
Spells - Good spells for udyr. Optionally, Udyr can increase his bonegrinding skills by Cleanse, releasing Udyr from any weakening tricks. Or Udyr can use Ghost to not be blocked by minions.
Masteries - this build does not makes Udyr stronger. It makes Udyr invincible. It makes Udyr bites your legs off. It makes Udyr have more hp at the beginning and take less dmg at the end. It makes Udyr beat King Arthur and Black Knight at once
Items - Let Udyr explain in points.
Udyr needs tanking boots, so if udyr encounters enemies with lotta magical dmg/stuns, Udyr needs Mercury Threads. If Udyr meets ad DPS, Udyr needs Ninja Tabi. Udyr needs only those shoes.
2 FROZEN MALLET
Udyr needs Frozen Mallet. Frozen Mallet gives Udyr nice amount of HP and bit of DMG. But most important for Udyr is slow effect - so they can feel Udyr's warm breath on their shoulders even better.
3 SUNFIRE CAPE
Another good item for Udyr. If there are ad enemies, of course. If Udyr is beaing annoyed by magical tricks, just jump to Banshee Veil. Udyr can make lotta profits with Banshee Veil. It is not shame to buy Aegis of the Legion, or second Banshee. Udyr will explain.
4 ATMA'S IMPALER
A MUST-HAVE for Udyr. Since Udyr has lotta HP - especially with those items - Udyr will have lotta DMG from it. Also, it gives Udyr piece of armour and 18% crit chance(tiger ftw).
If Udyr is doing good, udyr can take Infinity Adge instead of a HP item, or one of stackable items (Leviathan or Sword of Ocult). Udyr's choice.
Udyr is not fighting. Udyr is killing. Udyr is not chasing. Udyr is hunting for sport.
In early phases of the game, Udyr needs to play exptremely careful OR exptemely aggresive. Udyr must not give enemy any adventage. Since Udyr has no ranged skills, Udyr needs to run towards his enemies and scare them to die. Or at least stun them. It gives Udyr's teammates good chance to kite/kill enemies.
Udyr is not engaging fights. Udyr is making path of blood for his allies. Udyr needs to stun everyone he sees. Udyr must attack everyone in bear stance, to stun them. Then Udyr uses Tiger on squishy targets to kill them. Lastly, Udyr is using Turtle's mighty shell to prevent his enemies from harming Udyr's beautiful pelt. Even mightiest of Udyrs can die - but mostly when Udyr dies, Udyr's enemies bleed on Udyr's body. And be killed by Udyr's allies. Udyr fears no tower if armoured. Udyr soloes Tower. And enemy champion nearby first. Udyr is not fighting. Udyr is killing.