Arduvaar was a shrub related to mesquite, native to deserts (but not dune seas) and semiarid regions. When properly refined, arduvaar leaves contained an extremely powerful universal antidote.Arduvaar was prepared by boiling its tiny gray-green leaves in strong alcohol, then straining the extract. It could be used in this form, but in normal practice the extract was allowed to evaporate into powder, which had a much longer shelf life and could be measured much more accurately. The powder was then dissolved into wine or spirits and ingested.Even small overdoses of arduvaar were dangerous.