Considering that a UX designer is often required to carry out different roles within a UX team, does it also imply that a UX designer need to play multiple team roles. I find this rather conflicting because generally people of complementary personalities/behaviour trait work best in a team environment, and if a UX designer has to fill multiple roles then it can be in conflict with their own personality. In a company where there is no UX lead or manager (just UX designers) do they normally fit into the role of having to 'lead' or 'coordinate' between design and development or do they just end up trying to fit into the development process. I don't think that UX designers can just be a cog in the development cycle/sprint, but generally someone with a strong personality tend to upset the balance in the team.
My experience with UX designer roles is that they tend to either fit into a sprint cycle (as part of a step/process) or that they provide a deliverable for a particular sprint. I haven't seen UX designer that define the sprint process because they usually have to work with the scrum master or development lead.
The question is, in a UX team of more than one (including at least one UX designer, developer and graphic designer) and no lead role assigned, is it typical for the UX designer or developer to take the lead if the project relates to redesigning or refreshing the user interface (regardless if Agile methods are employed in the development process) or does it depend on other factors?