Timeless Child's regenerations

The Doctor's regenerations
Timeless regeneration cycle
First Doctor's regeneration cycle
New regeneration cycle
Other regenerations

About the Doctor

After falling off a cliff the first incarnation of the Timeless Child regenerated into the second.

This inspired Tecteun to want to study the effects of regeneration in order to transplant it into herself.

Her experiments triggered the child to have many regenerations. (TV: The Timeless Children)