Ireena was a red-haired woman who lived in Barovia. She was unaware that she was the latest reincarnation of Strahd's beloved, Tatyana. During a battle in Krezk, Strahd snatched Ireena and put her on his flying horse (the nightmare named Beucephalus). Strix cast hold person on Ireena in an attempt to rescue her, which caused her to fall to her death. Both Strix and Strahd were distraught over this.[1]
When the group returned to Barovia, they saw that the Abbot had put Ireena's head on Vasilka, the flesh golem bride.[2]