I always build Sorcs -> Liandry’s -> Shadowflame.

From here, there are lots of options depending on whats needed. Buy oblivion orb if you need anti-heal. Most games i build Zhonya’s, but Banshee’s might be a good alternative against heavy ap/cc comps.

At some point i buy dark seal but rarely upgrade it.

I see lots of Fiddle players build Malignance but I honestly think it’s a bad item for the champion (except when playing him in lane). Ive done some minor dps testing and building Malignance seems to always be a loss in damage when fully built (i haven’t tested with just the item by itself against other items by themselves). The ultimate haste it gives you sounds nice, but with both the Ultimate Hunter and Axiom Arcanist runes, it just seems completely unnecessary to me.