DaRealWario here, bringing you the guide to my first ever played Champion in LoL: Fiddlesticks! He is one of the best AP champs in the game because of his crowd control and spell-based tankiness. The build is costly, but very worth it. Fiddlesticks is a Jungler, Hit/Run, and Support, and once you master his combos you too will dominate your lane!

Pros
> High survivability mid and late game
> Massive damage output in 1v1 and 1v2 fights
> Use Jungling to your advantage: they keep tabs on lanes and creature buffs

Cons
> More AP = Bigger target for ganks
> Tanks and high AD can take you out fast
> Useless against spammed CC

Greater Glyph of Force x9

Greater Mark of Potency x9

Greater Seal of Force x9

Greater Quintessence of Force x3

Sorcerer's Shoes: One must be fast in order to slay enemy champs, right? Plus, early start on Magic Penn.
Haunting Guise: This provides a boost to AP, HP, and Magic Penn.
Void Staff: This helps with damaging enemies with your spells, plus it makes farming somewhat faster. This plus the Magic Penn. rune and Shoes will bring Magic Penn. to 88%
Rabadon's Deathcap x2: A must-have for nearly all AP users. It offers a base of 140 AP, which is boosted by 30% to 182 because of its passive. The Deathcap will boost other AP additions, but buying a second does not increase total AP by 60%.
Athene's Unholy Grail: Extra AP and Mana Regen, plus the useful passive that increases the regen based on how much Mana has been used.

Ghost: This is because Fiddlesticks may not be able to catch Champions late game with Crowstorm because they may be on edge. With this much AP, you are a marked ma...um, object. It also allows for the opposite. If you are ganked, use Ghost to zig zag through bushes and escape. Flash can only do so much for you, so its not as useful in the long run.
Teleport: Fiddlesticks is a decent Jungler/Assassin, so Teleport is a great shortcut tool for getting from one side of the map to a point where you are needed. Because you can warp to Wards, its a good way to retreat, get HP/Items, then get back in the action fast.

Heal: Drain's HP-restore power replaces this spell for the entire match, meaning you will never have the need for Heal.
Garrison: There aren't that many moments in game that require tower-hugging, and your allies would consider you useless if you keep losing a ton of HP and resorting to this.
Revive: Again, if you keep HP up with Drain, you don't need such spells. You are much better off with a Guardian Angel if you really must stay alive (it has a better CD and restore anyway).
Clarity: After you buy the Unholy Grail, this spell becomes somewhat useless. Beforehand, just use Mana Pots and the Mana Regen bonus from the Blue Buff.

<Buff> <AoE>
Lowers the Magic Resist of all units by 10, as long as Fiddlesticks is within range.

<Buff>
Applied to a single target. The Terrify buff is a combo of a Silence and a Slow, making it a good initiator for ganking or to escape. It only works on ONE target, so don't rely on it if you yourself are ganked by more than one champ, which will happen late game depending on your kill count. Don't use it if the enemy is running through minions, as you may end up wasting a combo starter.

<DPS>
The backbone of Fiddlesticks' survivability. Bountiful Harvest saps the target for a long time, dealing heavy damage in the long run and healing lost HP to you! Because this is channeled, it can be broken by Stuns, Silences, and other means, such as by Alistar gameplay. Be very sure you can pull off this move and get away afterward.
Base Damage: 900 (Before Magic Res)
AP Damage: 272.025 (Before Runes, Masteries, etc)
Total Damage: 2260.125 (Before Magic Res)

<Buff>
A good CC, depending on how many units are in your way. Reap will hit 5 times, but will bounce in the direction of any nearby unit after hitting the previous. This means it can hit some units more than once. It is better in CC, because it Silences all targets hit for a short time. If the same target is hit, the Silence time is reset!
Base Damage: 145 (x1) (Before Magic Res)
AP Damage: 272.025 (x1) (Before Runes, Masteries, etc)
Total Damage: 417.025 (x1) (Before Magic Res)

<AoE>
Summons wild crows for a short time, dealing intense magic damage to surrounding enemies. Because of the initial teleport, its a good initiator for solo or team ganks, as long as it it timed right.
Base Damage: 325 to 1625 (Before Magic Res)
AP Damage: 272.025 (Before Runes, Masteries, etc)
Total Damage: 597.025 to 2985.125 (Before Magic Res)

Gank: Fiddlesticks has two initiators in Dark Wind and Crowstorm, but such varied power is only useful if there is more than one target to jump.
Jungle: Fiddlesticks can patrol the bushes of the area to watch for counter-ganking, low-HP stragglers, and to keep tabs on Blue Buffs, the Dragon, and Baron.
Support: Dark Wind is a good CC in a team fight, provided there are no nearby minions to take some of the hits. He can also use Terrify on targets that are escaping or preparing to turn the tide of battle ( Requiem, Counter- Crowstorm, etc).
Assassin: Fiddlesticks can pop in on a lone target at anytime, use a Terrify/Drain combo, then escape into the night. Depending on HP and AP, you can tank Turret shots with this combo mid and late game to finish off Champions.
Tank: Fiddlesticks can only tank damage by repeated use of Drain, and if there is strategic CC nearby, this puts a stop to long life for some time.