"Favorite Lineage II Monster: Whichever one drops every piece of boss jewelry at 100% … let me know when you find it."
GM Sparse I found it!
If you take the long and winding road to Giran Of PTS you will find the Rabbit of Caerbannog (AKA elpy), should you succeed in killing this beast its has rate similar to which you seek.
Good luck my friend.
Forever thankful
Clarisa