Of all the afterlives to connect to Faerie, Thjazi wanted to connect the Dying Fields, where the orcs were trapped.
Was it because Aranessa had told him about the golden boats, and they had hoped to go to Faerie together?
Completely, definitely, absolutely off topic: Brennan dropped some lore in episode 16 that a dried aqueduct in the Endless Night was a diverted river from the mountains. “Some ancient sorcerer emperor snapped his fingers at the Tachonis and the Halovar and said, ‘Bring me a river,’ and they did.”
Anyway. Back on topic:
If Thjazi wanted to just save the orcs, all he needed to do was bridge Araman and the Dying Fields so that the lost souls could find the Old Path. Brennan noted to Aabria that the reclaimed souls looked lost in the woods, prompting her to Call the Corners and lead them along the path. To achieve that, Thjazi had brought the source of the River Gavzidra, a font of orc blood, to Dol-Makjar and had it remade into paint, then sent it to Hal to decorate the theater, turning the Dithyramb of Azgra into the Hallowed Round. He brought the source of the underworld river to the living world.
Why, of all the potential artifacts, did Thjazi steal the Stone of Nightsong, the elven psychopomp? If the new bridge needed three to be stable, why not steal something from the Tachonis and connect it to Tansul’s afterlife? They’re actually in Dol-Makjar anyway, and it was Tansul’s temple in the Endless Night that Thjazi raided to get the orc blood. The Stone of Nightsong was far afield in every way. He even had Occtis in his pocket if he wanted to be sneaky about it. Tansul’s artifacts would have been the logical choice.
But we learned in Episode 29 that the Stone didn’t take elves to their own afterlife; it took them to a place in Faerie.
Aranessa told Thaisha (and presumably Thjazi) about the golden boat to Faerie that was promised to all descendants of Royce. They didn’t go to the human afterlife created by Tansul; they had a pact with Faerie that pre-dated the Shapers. But we don’t know whether that was an option for non-descendants: for the spouses that married into the family. If it wasn’t, then Aranessa and Thjazi would have been separated in death—unless she chose the Old Path, and that would separate her from the rest of her family. She would have to choose, but even if they both chose the Old Path, the likelihood of being reunited is exceedingly low. The Hounds of the King and other reincarnated don’t seem to remember their past lives. Thjazi and Aranessa would probably be separated anyway.
As of the Seekers arc, Aranessa still expected to go to Faerie, even after seeing Thjazi’s funeral rites for the Path. However, she couldn’t be sure that it was still an option after the doors to Faerie had closed. She told Julien that she wouldn’t be afraid to look for the boat if he was with her. Thaisha suggested instead that Aranessa look for the Old Path, but we don’t know that Aranessa intended to. Thjazi had never returned to her, and she just lost all her family. We could hardly blame her for wishing to go to Faerie.
But Thjazi planned to use the Stone of Nightsong, the Hallowed Round, and the converted River/Paints Gavzidra to connect the Dying Fields, Araman, and Faerie.
Thjazi stole a river from the orcish underworld so that he could swim after Aranessa’s golden boat.
