A Linq-XML developer works with Language Integrated Query (LINQ) and XML in .NET applications. They use LINQ to efficiently query, manipulate, and transform data within XML documents. They handle tasks such as reading, writing, updating, and deleting XML data. They also work with XML schemas and namespaces, and ensure that data is correctly and efficiently queried and manipulated. They play a crucial role in data handling and management, improving application data access performance, and ensuring data integrity. They also use LINQ to XML for creating XML documents programmatically, parsing XML, or querying XML. They often work closely with other developers and stakeholders.