User blog comment:PitchBlack696/Nargacuga/@comment-4047763-20110606203344/@comment-969093-20110607083336

There isn't really much of a "tip" to give when it comes to getting rare items. :/ Cut the tail, kill/cap the bastard depending on if the item can be carved from the body and then pray. That's all there is to it. Remember, it's a luck-based game, not a pre-determined story like Final Fantasy. Keep on killing/capping and breaking and you will get it eventually.

If you have no luck in high rank/nekoth then you might wanna try G-Rank. Quite frankly I've never had any problems getting them myself. Just like Gravios Brainstems. I never cared a single bit about them and I get multiple almost every quest (when I still played unite).