What term describes an agent who has been granted power of attorney to act on behalf of a principal for unlimited legal matters?

The term that describes an agent who has been granted power of attorney to act on behalf of a principal for unlimited legal matters is a universal agent. A universal agent possesses broad authority to act on behalf of the principal in a wide range of matters, which can encompass almost any legal action the principal is capable of taking. This arrangement allows the universal agent to manage the principal's affairs comprehensively, unlike other types of agents who have specific, limited responsibilities or authority.

In contrast, the other options represent different scopes of authority. A limited agent (or limited authority agent) typically has constraints on what they can do, often restricted to certain transactions or functions. A special agent is appointed for a specific purpose or task, which limits their authority to that particular transaction. A general agent usually has broader powers than a special agent but does not possess the limitless authority characteristic of a universal agent. The distinction is important in understanding the variety of agency relationships and the corresponding authority granted to agents in different contexts.