The Maestro's mysterious ally.
ECHO is an unknown to Felix, but he trusts her with his life. (She reminds him of Anna.) She is his guide in the Matrix and into the life of a Technomancer. She tends to approve of his clandestine projects and lends information to encourage and support.
ECHO’s mystery is only furthered by her rescue and continued involvement with Sidestep.
ECHO is a core member of Subnet 12B.