请教这句话中的不定式是做什么成分呢？

问题描述

Deckard Cain the Elder is the only character aside from the title villain, Diablo, to appear in every installment of the series.

除了大反派Diablo，长者Deckard Cain是唯一一个贯穿系列的人物。

后面的不定式看起来是对前面的修饰，但是不知道在语法中应该叫做什么成分呢？

老师答疑

刘老师：

Deckard Cain the Elder is the only character aside from the title villain, Diablo, to appear in every installment of the series.

【答】不定式to appear in every installment of the series作定语，修饰the only character。

我把aside from the title villain, Diablo 这个介词短语的位置调换一下，就好理解了：

Aside from （=Apart from）the title villain, Diablo, Deckard Cain the Elder is the only character to appear in every installment of the series.