Who is The Shrike from The Rise of Endymion and what is their importance?

The Shrike is an assassin. He was created in the distant future by a faction of the Core known as the Reapers. The Shrike was then sent backward through time to aid Aenea in her quest to bring down the Church, as well as to expose the machinations of the Core. The Shrike is described as an intimidating figure. He is nine feet tall and covered in long metal spikes.