Blockcerts and Hyperledger Aries

I’m looking for someone familiar with both Blockcerts and Aries to explain how they relate and differ. I understand Blockcerts is a blockchain-agnostic framework for issuing and verifying credentials. This seems to be fit under the Aries umbrella, as it was built to provide interoperability between credential solutions, but I am not comfortable with how. Is that to say Blockcerts is an alternative to Indy?

Can someone expand on this further? Thanks!