No prizes for guessing what the hardest part of this costume was – and even more so considering it was only the second wig I'd ever styled, and the first was Yuffie's, which was not exactly on the same scale. Didn't get as much sideways-fluff in the final shape as I would have liked, but at least I got it all standing up in the main big spike. The white bits were a set of hair extensions that had to be sewn on separately, and gelled solidly in place.
Technically this is the Makai Arc version of Hiei's costume, not that this means much more than a red belt instead of the usual white ones and the excuse to make the tear-drop pendant to go with it (Hiei really does not vary his outfit much). Most of the rest of the costume was relatively straight-forward, but since there's no point in giving a costume multiple layers unless you can show them off, the coat had to be made so that I could take it off easily, which makes it the only coat I've ever made that's held together by velcro. To show off the third eye (made by printing the design onto temporary tattoo paper) the headband had to be removable without the whole wig going with it, so I wound up making it as a half-band that connected to the inside of the wig with a couple of press-studs.
The sword was modded from a wooden katana bought at a martial arts supply store, so only hilt had to be carved from scratch. But the fiddliest part of the costume would probably have to be the bandages on the hands, which were all sewn down on to a pair of gloves. By hand. Often one-handed, while wearing the glove on the other hand so I could see how all the fabric would stretch. (Oh, the things we do for cosplay.)