(PFP art credits: u/The_Omega_Yiffmaster on Reddit!) The Dryad is an NPC vendor that offers her services once you have defeated a major boss such as the Eye of Cthulhu. The Dryad is the last of her kind. She is connected with nature and can analyze its purity worldwide. She sells seeds, too! She is among the dryads who battled Cthulhu hundreds of years ago, unable to defeat it, but crippling it by rending parts of its body, forcing it to retreat to the moon. She went into hiding for years after.