This is a build for fiddlesticks focusing on his unique abilities and crowd control making him a formidable team player. The build is designed for 5 vs 5 battle and is NOT tested in 3 vs 3 battles. Feel free to test it for yourself and let me now ^^

We start of with the regular mage runes namely magic penetration, ability power and cooldown reduction. We equally divide those runes to have 10 of each stat for a good balance.

We pick the usual 9 offensive points for cooldown, ability power and magic penetration. Following up with 21 point for utility to boost mana, cooldown reduction, mana regeneration, speed, ect.

We start of withand a health potion since we didn't picked drain as our first skill. Reason for that is cause we focus on crowd control and spells on multiple targets. Now we either go mid or on lane which makes no difference for us. We harass our opponents with our first ability while silencing them making them easier targets for your partner. Exhaust is an extra bonus now to help your partner if you're on lane. Once we got enough we recall to base to upgrade it intofor increased cooldown reduction, AP and mana regeneration. Now when we return to the field we combine our abilities to harrass your opponents or render tem useless by giving them fear. Fear is very usefull in combination with drain and exhaust while making it easier for you to heal. Usually your team should have the upper hand now so we can farm a bit before we recall again to upgrade it intofor more of the previous bonusses and we also add some boots for more speed. We keep supporting our partner/team while we control our opponents way of moving with fear, silencing and exhaust, driving them right into your team's arms to be finished off. Once we farmed well enough as we'll be of use in team fights now we buyordepending on the teamwork and we upgrade our boots. Now we return to the field to support our team by either slowing them with your multiskills or by dealing more damage due to magic penetration. After we return for awe also get a void staff or rylai, depending on the one you got before. You'll be a real danger for opponents now especially when you appear in the middle of a teamfight with your ulti making you slow then and deal damage which makes them easy target for your team to finish it off. Now all we need is a finishing touch. I decided to get ato make your ulti something to be scared of. Due to your high AP and magic penetration it will deal alot of damage while rylai slows them to keep them in range. Now with this item it gets worse for them as you get healed by 30% of the damage dealt with your ulti. In combination with drain they won't get you down easy without all going death aswell.

Ghost: usefull for chasing opponents especially while your ulti is active.

exhaust: usefull early game and a good combination with your drain and fear or with your ulti.

other usefull spells: clarity (you're a mage) or flash (to escape).

pro's:
- massive ulti at late game making them scared of you alone
- good crowd control
- disables with multiple targets
- multitarget spells
- strong damage
- high survivability late game
- low cooldowns
con's:
- weak early game
- requires skill to use correctly
- targetted first in teamfights (so don't start in one, sneak in while its going on)
- works with the team

As you can see its a very usefull guy to have in your team and once you master it a very dangerous opponent for the enemies. I hope it'll help you guys, any feedback, tips or advise is welcome at the comments ^^