"Airini, Blessing of the Wind" is a body armor for Mirel when you made her a Sniper. If she is a druid for you, you get "Belduro, Nature's Protector" instead. You can't have both, as each is for a specific class of Mirel, and she can only be either Sniper or Druid.
Airini stats: ATK 32, DEF 22, M.ATK 22, +15% hit, +6% crit, ATK +20%, wind element damage taken -50%.