One huge Doctor Who fan theory about the Master has been validated by a recent Doctor Who release. This theory constitutes a bit of a retcon to previous Doctor Who episodes, confirming that a popular fan theory about what was really going on is actually true. This newly proven theory makes the Doctor’s long-standing relationship with the dastardly Master even more impressive. Going into Doctor Who season 15, this will be interesting, as the Master returns in a 2025 audiobook story that will sit nicely alongside the season’s episodes.

https://screenrant.com/doctor-who-master-regeneration-streak-war-chief-op-ed/