シスター完全敗北。〜無知なシスターが本能で発情交尾するまで〜

Helena, a novice sister working at the town church, harbors deep admiration for the beautiful and virtuous Lilia. Recently, she's been puzzled by a subtle change in Lilia's demeanor. The protagonist, Ivan, sets his sights on the unsuspecting Helena and uses his skills to attempt lewd contact. At first, Helena serves without fully understanding, but gradually, she realizes that this is what brings happiness to Lilia. The pure and innocent sister awakens to her instincts and begins to seek pleasure for herself... (Source: Fanza, translated) Note: Released at Comiket 105.