6.6 summary , please note it contains spoilers massive ones.
To summarize the Dottore situation :
Dottore split his soul in 2. One was sent in Nod-Krai (6.3) and the other one in the most secure vault of the Northland Bank, then used by Pantalone to upload it into the Ley Lines for his final experiment before going off completely (6.6)
By fusing into one he created his new weekly boss form
Nahida burned Irmimsul thus erasing him
OG Zandik died at 85 years old.
Pantalone has the option to create a completely new one without his soul since it got erased but with some of his memories plus Pantalones soul
We get an egg that can contain memories by the end
The Pyro Gnosis got lost and absorbed by the Traveler.
Also due to Fate changing.
Pantalone said : I might not be able to create a new Dottore.
Pantalone was his subordinate who got promoted to Harbinger.