Not Updated For Current Season
I jungle. This build enables me to jungle without Smite or Ignite. At level 4/5 I usually get first blood if they are pressuring a lane nearby, otherwise, I just keep jungleing untill I hit level 6 by killing the dragon. Then I try for a gank with my ulti.
I help out laning and later teamfigths. Always try and keep the golem buff up since there is no other way of getting mana back. Fiddle pretty much owns midgame as his abilities does a lot of damage but scales badly with the heavy AP he is getting for late game.
Fiddle gets a lot of mana - acturally at this point, he doesn't need the golem buff anymore, which is great since he should spend most his time being ready for a team fight.
Flash: Many prefer Ghost, but I use flash because I jungle. When jungling as Fiddle, you can get ganked very easily. Flash is great to escape in the jungle - especially when killing the dragon. Used with his ulti, Fiddle can instantly jump into the middle of a teamfight from a great distance.
Teleport: Often ignite, exaust or even Ghost are used in addition to flash, but I prefer teleport for several reasons:
1: Fiddle is slow. I can easily get to a bunch of minions and harvest some xp that would owtherwise be wasted.
2: If a lane is having problems or even if I just want to trick my opponents, I can teleport to a well placed ward and then use my ulti, leaving them with no time to call miss.
3: If the golem buff is taken or is just not safe to take, I can get back for mana without loosing the 30 seconds of xp while running.
4: If I die.
5: If I want to buy items.
6: If a team fight is going down with me out of position.
7: If I want to snipe a bunch of minions at a risky location, I can run there, kill monions for 15-20 sec and then teleport to a safe locations before the enemy gets to me.
8: If I want to defend a tower.
Drain owns. Many prefer Dark Wind early game, but drain is just too effective both offensively and when getting attacked.
I get level 1 dark wind fast in order to support my jungling, but from there on, I just go all out drain/fear.
This prevents me of being a good laner since my Dark Wind will stay level 1 until level 13.
This rune build is somewhat controversial! I have fould it to have some great advantages none the less. Magic penetration is just straight out nice. The armor, the CD reduction and the HP on the other hand all serve a single purpose; jungling. I never drop below 50% hp on the first golem - even without Smite/Ignite. I jungle faster and I have some great early game stats.
The Amplifying Tome and Health Potion is a must when jungling. Use the Health Potion to overcome the first golem easily.
Getting the soulstealer is really a personal choice. You can either sell you Amplifying Tome, make a Deathfire Grasp, make Solestealer or just keep it for AP. I prefer Soulstealer as it gives me extra motivation for not dieing.
Rod of Ages is a totally solid item. You get health which is much needed to survive enamies focusing you in team fights. You get mana which makes you less dependant on the golem buff mid/late game. And you get AP which scales badly with Fiddle's abilities, but is a must none the less.
Zhonya's Ring is amazing. The passive is great late game, but the active is just insane combined with his ulti. While it does prevent you from taking any actions such as dran or running, it does not cancel your ulti. In teamfights, you can jump in, fear/dran a target and when you drop low (and you will drop fast), you activate Zhonya's to bring the extra 2 seconds of pure pwnage upon your opponents and maby force them to switch target.
I jungle for 2 reasons. First of all, I have a high chance of getting first blood and maby even more kills early game. Secondly, the compined xp my team gets is increased since someone is laning alone and gettign the same xp as the players in mid. It has some potential consequences as well. You might get ganked in the jungle. This is why I use flash. Also, you want to make sure, thay the person laning alone is up for it. Morde is not only able to do this, but acturally often ganking when left alone with 2 opponents. A number of additional champions can do this - just remember that champions that usually go mid is not always able to deal with two opponents.