Hello everyone, i have been using this site for a few months and i think it's time to stop using it without helping other players, so this is my first build. First of all im sorry if a make a lot of mistakes or i right like an idiot, but im not from the US and my english is a bit rusty. the reason for which i thought of making this build is cause i've seen a lot of fiddles that put ability power before magic penetration, and looking at the horrible ap ratios and the basic damage on fiddles's skills, i realized than a high magic penetration
makes him much powerful against tanks, his main problem

for runes i choose magic penetration marks and glyphs because they give you 13 mp from level 1, and that means mucho more damage than the boost you would get from ability power runes.
i like the mana regen per level seals because your skills consume a lot of mana and that amount gets higher every level. and finaly i use the flat health quints because of the early boost they give you. if you get this and the doran's ring, u start with over 600 hp, very good for a level 1 caster. you can also use the magic penetration quints but i prefer the extra 80 hp before than the 5 mp u get frome them.

well this seems to be the best choice for almost every caster, gives you everything you need to be more balanced

this item build is made to do the biggest amount of damage and also to be able to destroy tanks, who can rape you in late game even if you have over 700 ability power.
the haunting gale is one of the best early items for fiddles, he gets hp, ap and mp, which are the three main stats for him. the order is not specific, you can choose to get the rabadons cap before the abysal scepter, and the void staff is not a must, you can change it for the banshees veil.
other items i recomend for fiddles are banshees veil if the other team is pure cc, a thornmail if you are being harrased by the dps champions.
the reason why i dont usually get a mejai's is because fiddles is always aimed and his ult puts him in a very dangerous position, so you can get killed very easily.
one last thing very important for him is to buy a lot of wards, if you place them correctly, not only will you have map vision, you will be able to teleport to certain places and ult unexpectedly. for example, if youre laning in top, and you are at the tower, put a ward in the bushes, and wait until a friend arrives, you now teleport to the bushes, then they will think he is alone in lane and will play offensively, thats the time to press R, Q, E, and W, the minions in the tower practically disapear and you have a double kill assured

well i hope this build is useful for someone, please try it before rating or commenting, i'll apreciate any critics or changes to be done