The Regeneration Limit

[u/DoctorAsh42]

I have a theory as to why Time-Lords have a twelve regeneration limit and just what it could mean for The Doctor now that he has exceeded that limit. In short, my theory is this: Every time a Time-Lord regenerates, they release more regeneration energy than the previous time. At some point, the Time-Lords decided that regenerating more than twelve times would release more energy than was deemed safe and thus, the regeneration limit was imposed. If we look at The Doctor's regenerations, they have always been accompanied by the release of some sort of light. Furthermore, the trailer for this year's Christmas Special seems to indicate that, special-effects restrictions aside, The Doctor has always released the same golden energy upon regeneration.

Considering this, we can see that The Doctor's first six regenerations saw The Doctor lying down and glowing with a small amount of light (this was also seen with the General's regeneration in Hell Bent). His seventh regeneration saw him release even more energy (the lightning effect used in the telemovie). Then, from the Eighth Doctor's regeneration in Night of the Doctor (his eighth regeneration) onwards, we've seen The Doctor standing up and expelling the familiar golden energy. I believe that the standing up aspect is due to the increased level of energy being released.

For the Eighth and War Doctors, the release of this energy still seemed fairly gentle, but when the Ninth Doctor regenerated, the energy was much more forceful. This was the same for the Tenth Doctor's first regeneration in The Stolen Earth/Journey's End (his eleventh overall). However, the Tenth Doctor's regeneration in The End of Time was famously violent, with enough energy being released with enough force, to actually destroy the TARDIS console room and send the ship crashing to Earth. Keep in mind that this should have been The Doctor's final regeneration and this is where I think my theory really picks up.

The next time we see The Doctor regenerate was in The Impossible Astronaut, but since this was actually the Teselecta and not the actual Doctor, this doesn't count. Of course, when The Doctor next regenerated properly in The Time of the Doctor, it was even bigger than the previous one, releasing enough energy to destroy the Dalek fleet above Trenzalore and send a shock-wave across the planet's surface.

Thus, we can see that over the course of the show's history, each of The Doctor's regenerations has released more energy than the previous one. If this pattern continues, then it could actually become dangerous for The Doctor to regenerate; endangering those around him. Especially since he still has another eleven regenerations to go for this cycle (including the upcoming one in Twice Upon a Time and not taking into account how this was affected by Davros in The Magician's Apprentice/The Witch's Familiar).

The only holes that I can find in my theory are River/Mels/Melody's regenerations, which shouldn't have released as much energy as they did (possibly due to her being a child of the TARDIS and not a true Time-Lady) and The Master's regeneration in Utopia, which, due to being part of his second cycle, should have been much more violent.

Anyway, that's my theory. Let me know what you think.

[u/Zal_430]

Doctor Who head canon, Chernobyl is just the Doctor taking regeneration a bit too far

[u/IntroductionOne6592]

A bit late to say but it's a pretty good theory! Just a shame that the timeless children happened.