Blockchain technology enables a significant reduction in the number of intermediaries in the financial ecosystem. It enables counterparties to engage in direct peer-to-peer transactions. However, this does not remove the need for a number of specialized players to exist in order for crypto-assets to fulfill some of their more complex and ambitious goals. As with any other financial system, crypto-assets require an ecosystem to flourish. In this chapter, we will explore a number of critical aspects of that emerging ecosystem.