Fiddlesticks was the very first champion that I ever learned how to play, so he really has a special place in my heart.
Fiddlesticks is interesting in that to be truly effective at playing him, you have to not only be familiar with the playstyle of a mage, but of an assassin to launch effective Crowstorms, a ranged carry to have the best use throughout the game with Reap, an AP carry because he is one of the few champions in the game with a truly game changing ultimate, CC because 2 out of his 4 skills are hard disabling CC and a 3rd is area denial, and a nuke.
What this guide does is give a little insight as to how I go about playing the Harbinger of Doom.

Warning: This is a fairly long, in depth guide, but it is full of information. I've made an effort to keep any superfluous comments out to keep it as short as possible, so please bear with me while reading it. Thanks!

Fiddlesticks is extremely powerful, however he is VERY easily shut out by anybody building up any kind of magic resistance.
Also, Fiddlesticks AP scalings are less than stellar, so instead of building up tons of AP, I build up magic penetration. What magic penetration does, is allow me to bypass all of the potential damage mitigation that might be built and allow me to deal 'true' damage.
I have tried to build up a lot of AP before, however this leaves him very vulnerable during the early and mid game and really leaves him susceptible to snubbing if he does not get fed very early.
What this philosophy does, is it allows me to have a lot of power throughout the game; early, middle, and late and it lets me have the ability to produce that game changing Crowstorm that turns the entire team fight into my team's favor.
In summary, a Crowstorm from a Fiddlesticks with 500 AP will deal 550 flat damage, however against an enemy with 30 magic resistance, you are actually dealing 385 points per second. Now, under this build, with an Abyssal Mask and a Rabadon's Deathcap, you have 324 AP but have a very strong chance of dealing 'true' damage, meaning that in effect, you are dealing 454 points per second, a 130 point differential per second and a 650 point differential for the full 5 second duration.

Magic penetration effects are applied in the following order:
1)percentage magic reduction
2)flat magic reduction
3)flat magic penetration
4)percentage magic penetration

So, according to the formula, the order of effects that affect magic resistance are applied in a certain order. This is important because while we do want to get through a lot of magic resistance, we don't want to be repetitive nor do we want to spend a lot of money on items that don't have a lot of impact.
So, in a game with the presented full build, the magic resistance effects from A Harmless Scarecrow and Abyssal Mask are applied first. Then, the penetration effects from your runes and Sorcerer's Shoes and finally, the percent magic penetration from your mastery, Arcane Knowledge to total out to 69 magic penetration and 10% magic penetration.

The other thing that I am sure you have noticed is that all of my other runes give magic penetration. This is VERY important to my early game damage. Let me explain:

Almost every single carry, whether physical or magic, ranged or melee, starts the game with about 30 MR. What this rune setup does is it makes it so that you start the game off with about 19 magic penetration from the metagame. To most AP champions, this is not enough to be worth giving up some of the other benefits that can be gained; however Fiddlesticks has something that is unique and that no other champion in the game has; A Harmless Scarecrow. This further reduces champion's magic resistance by 10, meaning that you start the game with a grand total of 29 magic penetration. Now add in another 10% magic penetration from Arcane Knowledge and you my friend, are dealing true damage at level 1. This is DEVASTATING. Just think, at level 1, you are dealing 65 damage per bounce with Reap or a maximum of 300 damage with Bountiful Harvest to an enemy with a 500 point health pool.

I use 2 mastery page setups for Fiddlesticks:

The biggest debate that any Fiddlesticks player has ever had is whether to start the game off with Reap, or Bountiful Harvest.
Well, I contend that they both have their uses and purposes in the lane.
Bountiful Harvest is the ultimate counter to melee champions because it makes any pester or attack by melee champions worthless. It nullifies any damage that was done to you, actually heals you back up, and does a lot of damage to them to boot. So, I typically start with this skill if I'm going to be in a lane with melee champions who have to get in close to me and stay close in order to do any damage.

Reap is a very damaging nuke early game, it silences, and it has a very large range, making it an excellent pester ability or long range barrage. Thus, I typically start with Reap if I'm going to be laning against a champion who uses abilities to deal damage or ranged enemies who don't have to get in close enough for me to use Bountiful Harvest to deal damage.
So, in a game, I don't pick a skill until I have actually gotten out to the lane and have seen who I am laning against.

In the overview, I said to start with Reap because that is the most common scenario. After that, I take a point in Bountiful Harvest for the sustain in the lane and then I take a point in Terrify for an extra second head start in case I'm ganked. After that, I take a second point in Reap for the extra damage and leave it until the end of the game because after the first 2 ranks, the damage falls off big time. I take my next point in Bountiful Harvest for the increased ability to 1v1 enemies and then I alternate ranks in Bountiful Harvest and Terrify and end the game by maxing Reap. Always take Crowstorm whenever it's up, levels 6, 11, and 16.
Most other guides focus around maxing one skill first, however this build doesn't. That is because Fiddlesticks has so many different methods and styles of attacking, that maxing one all of the way, leaves him lacking in other ways. For instance, maxing Reap first leaves him at a disadvantage when trying to 1v1 enemies because he can't sustain with Bountiful Harvest. Likewise, maxing Bountiful Harvest first is not the best way to go because without somebody applying a hard CC, it is nearly impossible to get the full damage from it. As for Terrify, it's a very powerful CC ability, however maxing this first means that you have nothing to follow it up with, leaving you free for 3 seconds and then dead after that.

-This item does give a lot of early game AP, however during the late game you only increase you AP by 80 and get a passive that is extremely repetitive since you have Bountiful Harvest and, in order to maximize its effects, you have to get it during the early game. Doing this decreases the availability of other more important items in the build like Fiendish Codex that give cooldown reduction, mana regeneration, and very comparable AP, or the easy purchase of Zhonya's Hourglass. So, in summary, the stuff that you give up is just too valuable in order to get a passive that you get anyway from one of your abilities.


-This is a very valuable item since it gives several bonuses for a very cheap price. My biggest complaint for this item is that it doesn't build into anything. Normally, this is acceptable, especially for carries, since they require early game benefits in order to last long enough to build into their more important items. However, since Fiddlesticks becomes 10x more powerful at level 6 without any item contribution, he can afford to give up that early game benefit in order to build more into his mid and late game.


-Referring back to the section The Magic Penetration Formula, we know that since Void Staff gives percentage magic penetration, it is applied last. And, since we already get through so much magic resistance, the purchase of Void Staff is almost useless since by the time its effects are applied, the magic resistance that it has to work with are almost gone, severely lessening its effectiveness.

Cooldown Reduction:




Tank Killer:





Defensive:





Matchsticks:

Fiddlesticks excels as a massive AOE nuke that wins teamfights and is one of the best disablers in the game. During a teamfight, you can instantly kill a champion of your choice by using Crowstorm, Reap, Terrify, and Bountiful Harvest on the same target. But, LoL is a team game, so unless there's just one carry that has to go, use you abilities to benefit the entire team.
Use Crowstorm, and then Terrify the Carry or champion who is dealing the most damage. This will severely reduce the amount of damage your team is taking. Next, launch a Reap at the tank or character who is giving the most CC. This will silence them and stop the other team from stunning/silencing your team. From there, turn around and start to Bountiful Harvest the Champ who has the biggest damage output(this is usually the Carry that you just hit with Terrify). Now, you have wiped out their damage, and blocked out their CC. Without these 2 factors, their team has no choice but to fall back. Now, if they have 2 champs with large DPS, hit the second champ with Exhaust. This will slow and further reduce their damage output as well as making them more prone to die from your Crowstorm or another teammate's attacks.
Unless you are fighting 1v1 or are getting killed, DO NOT Exhaust and Terrify the same target. Reap will hit at the bare minimum 2 champions and silence. Terrify affects another, and your Exhaust should take out another. 1v5 hold pretty good odds in your favor as opposed to wasting a perfectly good ability on a target that is no longer a viable player in the fight.

• When getting ganked, even a rank 1 Terrify will give you enough time to make a break for your turret.
  
  
• Likewise, using it on an aggressive laning enemy can catch them off guard and lead to you and your lanemate dealing a lot of unanswered damage.
  
  
• Casting Terrify under an enemy turret will not pull aggro, so when attacking the turret, you can give you and your lanemate a few more attacks by using Terrify on the enemy that has tried to come to its aid.
  
  
• Channeling Crowstorm from the bush will lead to the enemy not knowing when you're going to attack.
  
  
• Using the blink from Crowstorm and then following with a Flash lets you 'double jump'; effectively allowing you to hit a group of enemies with Crowstorm from off of the screen.
  
  
• Terrify into Bountiful Harvest is a fairly basic combo that lets you get a few seconds of uninterrupted drain in. However, this only really works around rank 3 of Terrify since an extra .5 seconds is very rarely worth the extra mana cost early game.
  
  
• Reap has a longer range than Terrify, so when chasing, it is sometimes beneficial to launch Reap in order to make it impossible for the enemy to use Flash or any other ability that would allow them to get away.
  
  
• Terrify at rank 5 keeps an enemy in place for 3 seconds. It takes 1.5 seconds for Crowstorm to channel; meaning that it is possible to use Terrify on an enemy, and then use a point blank Crowstorm into Exhaust, Reap, and Bountiful Harvest to take on a more powerful enemy.
  
  
• Likewise, if you're being chased, running into a bush to break line of sight and then either starting the channel or Crowstorm or waiting for them to get close enough to cast Terrify can quickly turn the hunter into the hunted.

Fiddlesticks is one of the few champions left who can truly impact the game for the better of your team. His ultimate is a guaranteed teamfight victory and his CC makes him a valuable asset anywhere you go.
Basically, get good with him. Truly good fiddle players are an asset to the entire team with their huge damage potential, game changing ultimate, and vast array of CC.