What religion did the aryans bring with them when they invaded India?

There is no historical evidence to support the notion of an "Aryan invasion" of India. The term "Aryan" is a broad linguistic classification referring to a group of ancient Indo-European languages, and it does not equate to a specific ethnic or religious group. The primary religious tradition of the Indian subcontinent at the time referred to as the "Vedic period" (c. 1500-500 BCE) was Vedic religion, which developed among Indo-Aryan-speaking communities in ancient India.