Complex sentence: Trish is initially introduced in "Devil May Cry" where she hires Dante to help stop Mundus's plan to conquer the human world by opening a gate to the demon world on Mallet Island.
Split into simpler sentences: Trish is initially introduced in "Devil May Cry". In "Devil May Cry", she hires Dante to help stop Mundus's plan to conquer the human world by opening a gate to the demon world on Mallet Island.