As observed by the Twelfth Doctor, the "state of grace" was the period before regeneration when a dying Time Lord could resist the changing process without consequence for a limited time where they were restored to full strength. During this period of time, the Time Lord would choose whether or not they would ultimately regenerate or refrain from doing so, as they would grow weaker and eventually perish if they did not fully regenerate soon after the process began. (TV: Twice Upon a Time [+]Steven Moffat, Doctor Who Christmas Special 2017 (BBC One, 2017).) While a state of grace could be voluntary, some forms of death could induce a similar state unless they received aid. (TV: Planet of the Spiders [+]Robert Sloman, Doctor Who season 11 (BBC1, 1974)., PROSE: Love and War [+]Paul Cornell, Virgin New Adventures (Virgin Books, 1992).)
Should a Time Lord stay in the state of grace for longer periods than necessary before undergoing a regeneration, the resulting regeneration energy will build up to such an extent that, once the process is finally allowed to begin, it can become highly explosive, causing a significant amount of damage to anything close by from the expelled regeneration energy emitting from a regenerating Time Lord, (TV: The End of Time [+]Russell T Davies, Doctor Who Christmas Special 2009 and New Year Special 2010 (BBC One, 2009-2010)., Twice Upon a Time [+]Steven Moffat, Doctor Who Christmas Special 2017 (BBC One, 2017).) however, the regeneration process will proceed as normal if the state of grace is ended early enough by the Time Lord going through with the impending change, (TV: The Parting of the Ways [+]Russell T Davies, Doctor Who series 1 (BBC One, 2005)., The Time of the Doctor [+]Steven Moffat, Doctor Who Christmas Special 2013 (BBC One, 2013)., The Power of the Doctor [+]Chris Chibnall, Doctor Who Centenary Special 2022 (BBC One, 2022).) or if they are rendered unconscious just before regenerating. (TV: The Caves of Androzani [+]Robert Holmes, Doctor Who season 21 (BBC1, 1984).)
The state of Grace can also end on its own once a Time Lord has exceeded how long they can continue being in it, causing immense pain depending on the circumstances leading to the Time Lord's regeneration. (TV: The End of Time [+]Russell T Davies, Doctor Who Christmas Special 2009 and New Year Special 2010 (BBC One, 2009-2010).)
History[]
The Doctor[]
The First Doctor, fearing the change, held off his own regeneration for several hours. However, unlike his future incarnations, the Doctor's face did not stay the same, becoming "all over the place" while in the state of grace. When the Doctor regenerated, he passed out as his state of grace ceased. (TV: Twice Upon a Time [+]Steven Moffat, Doctor Who Christmas Special 2017 (BBC One, 2017).) However, his regeneration was comparatively peaceful than when his future selves regenerated after halting the process (TV: The Tenth Planet [+]Kit Pedler and Gerry Davis, Doctor Who season 4 (BBC1, 1966).)
When the Third Doctor contracted radiation poisoning on Metebelis III, (TV: Planet of the Spiders [+]Robert Sloman, Doctor Who season 11 (BBC1, 1974).) he spent ten years drifting in his current form in his TARDIS before he finally died upon returning to UNIT, (PROSE: Love and War [+]Paul Cornell, Virgin New Adventures (Virgin Books, 1992).) only regenerating with the aid of K'anpo Rimpoche. (TV: Planet of the Spiders [+]Robert Sloman, Doctor Who season 11 (BBC1, 1974).)
The Fifth Doctor was able to hold off his regeneration from Spectrox toxaemia for several hours (AUDIO: Winter [+]Paul Cornell, Circular Time (Main Range, Big Finish Productions, 2007).) while trying to retrieve the bats' milk needed for the antidote but finally accepted the need to regenerate when he was only able to acquire enough antidote for his companion, Peri. (TV: The Caves of Androzani [+]Robert Holmes, Doctor Who season 21 (BBC1, 1984).)
The War Doctor managed to hold off his regeneration for "years", (PROSE: The Day of the Doctor [+]Steven Moffat, adapted from The Day of the Doctor (Steven Moffat), Target novelisations (Target Books, 2018).) although it's unclear if this was a state of grace or the Doctor simply holding back his need for it as he regenerated due to his age, not illness or injury.
The Ninth Doctor momentarily delayed his impending regeneration to explain what was happening to Rose Tyler. (TV: The Parting of the Ways [+]Russell T Davies, Doctor Who series 1 (BBC One, 2005).)
After subjecting his body to a lethal amount of radiation, the Tenth Doctor delayed the regenerative process long enough to revisit each of his former companions from his own incarnation and his past selves as well (TV: Death of the Doctor [+]Russell T Davies, The Sarah Jane Adventures series 4 (CBBC, 2010).) in a "final reward" before he ultimately regenerated, which severely damaged the TARDIS. A few minutes before the regeneration began, his "state of grace" ended causing the Doctor to experience excruciating pain, resulting in him collapsing to the ground, barely possessing the strength to reach his TARDIS. When the Doctor finally underwent his regeneration, the amount of time he spent delaying the process caused an explosive regeneration that severely damaged the TARDIS, and left the newly regenerated Doctor crashing back onto Earth. (TV: The End of Time [+]Russell T Davies, Doctor Who Christmas Special 2009 and New Year Special 2010 (BBC One, 2009-2010).) The damage was so severe that the TARDIS was forced to undergo its own regeneration to recover from the damage. (TV: The Eleventh Hour [+]Steven Moffat, Doctor Who series 5 (BBC One, 2010).)
When the Eleventh Doctor was granted a new regeneration cycle on Trenzalore, he was able to use the energy from the resulting "reset" to regress his body to a younger state and hold back the regenerative process for a time. (TV: The Time of the Doctor [+]Steven Moffat, Doctor Who Christmas Special 2013 (BBC One, 2013).) During such, he took his last meal of fish fingers and custard (which he had first had shortly after his previous regeneration), phoned his personal future to ensure Clara Oswald stayed with his future self, (TV: Deep Breath [+]Steven Moffat, Doctor Who series 8 (BBC One, 2014).) and later said goodbye to his companion before finally undergoing a full regeneration. (TV: The Time of the Doctor [+]Steven Moffat, Doctor Who Christmas Special 2013 (BBC One, 2013).)
When severely injured by a Cyberman, the Twelfth Doctor was able to resist regeneration for several weeks despite struggling to walk. He further resisted it despite numerous Cybermen mortally wounding him, buying himself time to ignite Floor 0507. However, he struggled to hold it off when revived in the TARDIS, nearly regenerating completely. (TV: The Doctor Falls [+]Steven Moffat, Doctor Who series 10 (BBC One, 2017).) The Twelfth Doctor encountered the First Doctor at this time, who was also in a state of grace, holding back his regeneration as he feared regenerating. Throughout this time, the Twelfth Doctor steadily grew weaker, nearly collapsing at one point while at Villengard and having to sit down for a few minutes to recover. After the adventure, both Doctors chose to regenerate. While holding his regeneration back a little longer to make an advisory speech to his future incarnation, the Twelfth Doctor continued to grow weaker and collapsed to the floor just before his regeneration occurred though he managed to stand up once more by leaning on the TARDIS console to help him to his feet. Similar to the Tenth Doctor's regeneration, the Twelfth Doctor regenerated explosively, causing the control room in the TARDIS to explode. (TV: Twice Upon a Time [+]Steven Moffat, Doctor Who Christmas Special 2017 (BBC One, 2017).)
The Thirteenth Doctor momentarily delayed her regeneration in order to take Yasmin Khan on one last trip, observing the Earth from the TARDIS and eating ice cream, before dropping her off back in her time and landing elsewhere to finally regenerate. This regeneration was far more peaceful than the Doctor's previous regenerations. (TV: The Power of the Doctor [+]Chris Chibnall, Doctor Who Centenary Special 2022 (BBC One, 2022).)