Intro:

Welcome to my guide. This is my first one, so please bear with me. I will update and work on it as I go. I'm writing this because I feel like Shen is often viewed as merely a tank, which completely overlooks the fact that Shen is a flippin' ninja. If you implement this build, I promise it will change the way you look at Shen.

v1 Creation of guide

v1.1 Altered build order, more info added

So I'm sure most people wonder why you would do this rather than the traditional tank builds. Simply put, ever since the Nautilus patch, Shen's passive, Ki Strike, no longer has it's cooldown lowered by being hit. Now it's lowered every time Shen uses his auto-attack. This one change made me alter my entire view of Shen. Being able to proc Ki Strike multiple times will help keep your energy up and deals boatloads of damage, especially when used with Feint, which doubles the effect of his auto-attacks cooldown. Also, a tank that is no threat at all cannot hold any team aggro beyond what he forces with his abilities. If you build as a pure tank with only defensive items, you're going to be ignored as soon as Shadow Dash wears off, assuming that the other team is smart. Building Shen as laid out in this guide will help keep focus on you because you are nearly as much of a threat as any other player on your team. Also, this build is intended mostly as a bottom lane support, but works just as well as a solo top.

The masteries have been chosen to help give Shen a little tankiness to start. The build doesn't give him much in the way of survivability until you begin building Warmog's, but once you begin to build that, Shen is nearly unstoppable. The runes will give Shen a nice boost on his health, which makes Ki Strike do more damage and increases the heal done by Vorpal Blade. The magic penetration runes will give a little more OOMPH for his passive and Vorpal Blade and cooldown runes to help with spamming skills.

So into the nitty gritty of our build. To start you'll want to begin with Ruby Gem. This will give you a bit more survivability and increase Ki Strike and Vorpal Blade's effectiveness. On your first trip back you'll want to grab Heart of Gold to begin generating gold without taking minions from your lane partner. Also make sure you grab a sight ward for your carry to help prevent ganks and place it near dragon. On your next trip you'll want to at least grab Boots of Speed and more sight wards. If you have picked up a few kills/assists since the last time back then grab Kindlegem as well. Grab Zeke's Herald as soon as you're able. Since your typical team composition is going to be you as Shen and an AD carry on bot, this will go a long way towards powering up your lane partner and keeping them alive, not to mention a nice cooldown bonus for yourself. Finish off your Mercury Treads after this to take the edge off AP burst damage and CC's and start building your Warmog's to start really beefing Shen up for the mid/late game team fights. Building Zeal after Warmog's will kick up your damage output by a nice amount, but shines mostly in the movement speed buff to help you get to allies in trouble and chase down any fleeing enemies. From here, it's situational. If your team is way ahead of the other team on gold and you are getting fed with kills and assists, go ahead and finish off Zeal into a Phantom Dancer. If not, then start building Randuin's Omen/Thornmail or Force of Nature as the situation requires first.

I always start with Vorpal Blade at level 1. Why not Shadow Dash? Well, the cooldown at level 1 is 16 seconds and only lasts for 1.5 seconds. Not so useful for your first fight down in bottom lane. Vorpal Blade on the other hand will be up every 6 seconds and deals 60 damage each time. Considering that your typical carry will begin the game with less than 600 HP, this will deal about 10% of their health on each attack. Grab your Shadow Dash next followed by Feint. Max your Vorpal Blade first to keep up with the growing health of the opposing team. Maxing Feint second will help keep you alive throughout the game. Max Shadow Dash last to help lower the cooldown and you can use this not only to save your team but also to chase down fleeing enemies.

Your main goal as Shen is to be a nuisance to the opposing team and a boon to your own. The build and summoner spells will help you to be at hand as soon as possible whenever fights break out. Between the Teleport summoner spell, Stand United and Zeal/Phantom Dancer, you will have great map coverage for being in fights. With that said, let's look at style on different phases of the game.

Level 1-5: Your first move will either be to cover your jungler from an enemy invade or to get into the bushes in bottom lane as quickly as you can. Since you're only buying the Ruby Crystal, you can easily get a 5-10 second head start on other champions and be in the bush close to the enemy turret. Do NOT try this against an enemy Blitzcrank or Nidalee as you're likely to wind up grabbed/nailed with a spear. However, other champions will often wind up face checking the bush. Drop Vorpal Blade on the squishier champ and get the first blood if possible. If you or your partner pick up a kill then go back to your base and grab your Heart of Gold to start generating gold ASAP. Use your Vorpal Blade to keep your partner healed and wait for the chance to pounce on the enemy squishy with a Shadow Dash/Vorpal Blade/Ki Strike combo and back off unless you're positive you can secure the kill. Your main goal here is to zone the enemy carry out from farming gold/xp and give your own carry a safe zone to farm.

Level 6-11: By now, you should have Heart of Gold and Boots of Speed at least. Begin watching for your top and mid lanes to be ganked by the enemy jungler and be ready to use Stand United to keep the gank from succeeding. The best use of Stand United is to stop the initial burst damage rather than to save someone that is almost dead and being attacked by 2 or more enemies. Remember, the shield on your ult is nice, but it's most important function is to get you next to someone in trouble and save them with Shadow Dash/Vorpal Blade. If your partner in bottom lane is playing smart, try ganking mid to give them the advantage in their lane as well.

Level 12-18: At this point, you should be close to or have your Zeke's Herald, Mercury Treads and be close to have Warmog's. You will have good survivability and will be putting out a DPS that is fairly close to the carries on your team. The gap between you and the carries will widen as the game goes on, but that's because you'll be stacking armor/magic resist as needed. A good strategy is to stick with an AD carry so that they get the benefit from your Zeke's Herald and Vorpal Blade to keep them sustained in fights and quickly take down towers. When team fights break out, make the smart decision for your team. Instead of initiating team fights with Shadow Dash, think about how to shut down damage and isolate enemy AD carries. Nunu winding up Absolute Zero? Shadow Dash and stop it from reaching full damage. Warwick jumping on your carry? Shadow Dash and stop the damage and give your teammate the chance to fall back behind your lines. Other priority targets include Katarina and her Death Lotus, Ezreal's True Barrage, Karthus's Requiem (if he's dumb enough to channel it near a team fight while still alive), Malzahar's Nether Grasp or pulling Fiddlesticks from the middle of your team when he jumps in with Crowstorm. Until you get Shadow Dash leveled up, you'll need to prioritize who to shut down. If you don't have one of the high value listed above, pick out the enemy doing the most damage to your team. Remember, once you have Warmog's, you're going to be very difficult to kill with your team there to support you, so get in there and mix it up!

With this build I like to use Ghost and Teleport. Feel free to alter this, but I feel that Ghost has a lot more utility for Shen than Flash. Teleport will make you seem like you're everywhere. It's incredibly satisfying to ult to an ally in trouble, kill that enemy, see your lane being pushed by the enemy, Teleport back to your turret and kill that enemy as well.

I know this guide is pretty bare bones at the moment, but I hope it makes you think differently about Shen. I'll pretty it up as I go along/have the time. Please try it before you downvote it, and if you have constructive criticism, I'm always happy to consider it. Constructive being the keyword here folks. Also, this build has been extensively tested only in regular games on Summoner's Rift. Your mileage in ranked or Dominion may vary.