My rune set-up is 9 magic penetration reds, flat armor seals, CDR blues, 2 HP regen quints and 1 flat HP quint. 9/0/21 masteries, Cleanse and Ghost as summoner spells.

As far as skills go, R->Q->E->W is order of priority, as long as I pick up one rank of W at either level 2, 4, or 8 (depending on circumstances).

I start with a Regrowth Pendant, which gives me a total of 29 HP5. I can totally shrug off most harassment, which generally keeps me in lane longer and gets me more last hits in. Once Q gets a few levels on it (3 or 4) I can harass back pretty hard from a long range simply by bouncing it off minions. Although this generally pushes the lane straight up to their tower, I can keep hitting them under their tower with Bouncing Blade and Killer Instincts until they're either a) forced to recall or b) keep tower-hugging like idiots waiting for me to dive them.

Before going for any kind of damage item, I grab shoes (Merc Treads, 95% of the time) and Heart of Gold. After that, I go for a Gunblade, Rageblade, and another Gunblade - turning the HoG into Randuin's Omen and the Regrowth Pendant into FoN where I see fit (although if up against Mordes/Lots of Ignites I'll get QSS for an MR item instead).

The combined armor and MR make me quite beefy and still let me output a ton of damage due to Kat's amazing scaling. I still need to poke around with what happens if I use Randuin's active during Death Lotus (I'm unsure as to if it interrupts or not - I usually use the active right before hitting R).

I plan to try different things with rune set ups once I get more IP, but this has worked pretty nicely for me over the last couple days. I might replace the CDR glyphs with MR glyphs.

Blade Fury (F)
Causes a bladestorm of destructive force of 200 AoE around Yurnero, rendering him immune to magic and dealing damage to nearby enemy units and buildings. Lasts 5 seconds.
Level 1 - Deals 80 damage per second.
Level 2 - Deals 100 damage per second.
Level 3 - Deals 120 damage per second.
Level 4 - Deals 140 damage per second.

Healing Ward Healing Ward (G)
Summons a Healing Ward that heals units` within 500 AoE. Ward can move slowly, has 5 HP and 0 medium armor. Lasts 25 seconds.
Level 1 - Heals 2% of hit points per second.
Level 2 - Heals 3% of hit points per second.
Level 3 - Heals 4% of hit points per second.
Level 4 - Heals 5% of hit points per second.
• You can order the Healing Ward to move (movespeed 300).

Blade Dance Blade Dance ©
Yurnero`s cunning blade gives him a chance to deal double damage on each attack.
Level 1 - 10% chance.
Level 2 - 18% chance.
Level 3 - 26% chance.
Level 4 - 36% chance.
Mana Cost: N/A
Cooldown: N/A
Omnislash Omnislash (E)
Yurnero moves around the battlefield, slashing many enemies. Yurnero becomes invulnerable while Omnislashing. The search area is 450.
Level 1 - Unleash 3 (5*) blink strikes.
Level 2 - Unleash 5 (7*) link strikes.
Level 3 - Unleash 8 (10*) blink strikes.
Mana Cost: 200/ 275/ 350