Business analysis have process that involves the understanding of stakeholder. This process is called stakeholder analysis. This process is covered with assumptions made during during projects formation in Waterfall SDLC. Similarly, these stakeholders analysis can be conducted with Agile approach.

Agile your Knowledge of Stakeholders
In traditional project, we usually set a baseline on the understanding of stakeholders. As project progress, we seldom revisit or update our understanding of stakeholders. In an Agile project, stakeholder analysis become similar to your project cycle. Your knowledge of stakeholders are constantly updated with each Sprint.
Agile in your Stakeholder Analysis
Agile is result driven and focus on positivity in clearing the backlog. There is always a bad or black spot in all stakeholders. Like Agile, your stakeholder analysis must be aligned with positive nature and definition of done. Another key area in your analysis is to seek out close collaborator among your stakeholder. Not all stakeholder suits Agile and your analysis must identify Agile stakeholders.
Stakeholder analysis differs from Waterfall to Agile approach. You will need to seek out stakeholders who suits Agile in the course of your Agile project. The stakeholder analysis requires deeper understanding and iteration similar to your Agile.