The Dendro Gnosis, peacefully obtained from Lesser Lord Kusanali by Il Dottore in exchange for information about the rumor that "the skies of Teyvat are fake."
He's obsessed with the idea of "fair exchange," to the point of wanting to overthrow the natural imbalance between gods and humans. But, I guess it's just how ordinary mortals are like — it's easy for them to come up with pointless delusions.
Currently, there is no hint as to what Vision (or Delusion) Dottore will hold as a playable character, or even as a Harbinger. Judging purely by his design, he appears to be a Cryo or Hydro Vision holder.
Il Dottore is the Second of the Eleven Fatui Harbingers that enforced the will of the Tsaritsa of Snezhnaya across Teyvat, and was known as an eccentric genius who conducted unethical experiments to create "enhanced humans." Il Dottore is a former resident of Sumeru and former student of the Akademiya academy.
Dottore in the Genshin Impact 3.2 Archon Quest
Nahida agrees to give him the Electro Gnosis but only if Dottore erases all his other segments. Somehow, Dottore manages this, and Nahida even confirms that he's successful.
Collei is quickly revealed to have connections across the cast. A Fatui Harbinger — the title members of the Fatui leadership — named Il Dottore previously kidnaped Collei, and she befriended characters from Mondstadt such as Amber during her escape.
2 – Il Dottore alias The Doctor.
After Niwa succumbed to his wounds, Dottore cut his still-warm heart out of his chest and placed it into the device.
The two worked together to create a new artificial god, Shouki no Kami, using Scaramouche and the Electro Gnosis as a power source for the body. After Scaramouche's defeat, Dottore expressed a disappointment in the conclusion of his experiment, and left Scaramouche behind.
Dottore takes interest in Diluc's vision, mentioning that it is different from normal ones. This seems to imply that some vision users may be canonically more powerful or even possess hidden powers.
Dottore's real name is Zandik, and though some may assume he comes from Snezhnaya due to his Harbinger affiliation, he's actually a Sumeru native.
Various Genshin Impact leaks state that Arlecchino and Dottore will be playable characters in the future, with the former possibly being summonable in a Fontaine patch.
Dottore's history, as we know it
But before coming to Mondstadt and becoming a Fatui Harbinger, Dottore was a scholar in Sumeru.
As we know, Il Dottore made eight segments of himself and set them to various tasks, until the Omega Build decided to sacrifice the other seven in exchange for the Electro Gnosis.
During the cataclysm five hundred years ago, the previous Dendro Archon, the Greater Lord Rukkhadevata, perished after trying to completely remove the forbidden knowledge from Irminsul.
Who betrayed Scaramouche Genshin? Scaramouche was disgusted to learn that his second "betrayal" was masterminded by Dottore and decided to atone by erasing himself from Irminsul as the kabukimono and his Fatui codename in an attempt to give his former friends a second chance.
Dottolone is the slash ship between II Dottore and Pantalone from the Genshin Impact fandom.
In Childe's newest (leaked) Voiceline, he mentioned that Dottore took segments of himself at different ages who are assigned different tasks, basically "cloning" himself.
Pierro is the 1st of the Fatui Harbingers. He's the very first member of the Fatui who only shows up during important occasions.
Tartaglia: More popularly known as Childe, Tartaglia is No. 11 of the Fatui Harbingers. He's also the only playable character from Snezhnaya at the moment. Despite being the youngest member of the Harbingers, he's always eager for a challenge and is a fearsome foe, wielding both a Vision and a Delusion.
Kaeya, who discovered that Collei was the culprit behind the dark fire and was set to kill her, spared her life and resolved to aid her as well.
The God of Wisdom's enemy is wisdom itself. Lesser Lord Kusanali used to be the name floating around Genshin Twitter about the Dendro Archon. Now, after the Sumeru Archon Quests, it feels more natural to call her by her preferred name: Nahida. Those two names are one and the same, as they both refer to a single person.