Finger Bearers begin as cursed wombs where they gestate until birth. During this period they can be seen by non-sorcerers. Once born they create an Innate Domain, a precursor to a Domain Expansion, that warps the dimensions of its birthplace.
Finger Bearers possess the normal abilities of a cursed spirit but they are incredibly powerful due to possessing one of Sukuna's Fingers. So far they are shown to be intelligent cursed spirits with a perchance for cruelty and toying with their opponents, much like Sukuna himself.
Finger Bearers act like regular curses and tend to linger at their point of origin and attacking any individual that enters their domain. They also possess incredible amounts of cursed energy, being able to fire it out in unrefined blasts and even barriers.
However, despite their strength, they seem to lack any form of cursed technique and pale in power when compared to Sukuna.
During the mission to confirm and rescue any possible survivors at the Eishu Juvenile Detention Center, Yuji and Megumi encounter a Finger Bearer that was born from the previously reported cursed womb. The spirit slices Itadori's left hand off before the boy attempts to buy time for Fushiguro to rescue Kugisaki. Once Megumi and Nobara are out of the center, Yuji switches with Sukuna. The King of Curses initially attempts to cooperate with the Finger Bearer, but the cursed spirit attempts to kill him, only to get completely overpowered. Sukuna is somewhat amused by the special grade's efforts, but in the end he activates his Domain Expansion: Malevolent Shrine and exorcises the Finger Bearer, taking his finger afterwards.
Another Finger Bearer was encountered by Megumi in the domain of the cursed spirit under Yasohachi Bridge. After exorcising the mole curse, Megumi is surprised to find the domain still intact, whereupon the Finger Bearer emerges to confront him. Megumi quickly realizes that the finger of Sukuna inside this curse caused the mole curse to awaken and start claiming victims, and prepares to exorcise it.
However, the Finger Bearer proves to be several degrees stronger than it's counterpart in the juvenile detention center, thoroughly overpowering Megumi and breaking his sword, with only his Shikigami saving him from certain death. Nevertheless, the Bearer knocks out Megumi temporarily, forcing him into a corner. This leads to Megumi seriously considering a last-ditch tactic, only to scrap it in favor of trying out an incomplete Domain Expansion. The curse is temporarily overwhelmed by the combined attacks of the Shaman and his Shikigami, but is ultimately able to dispel the domain using a blast of explosive cursed energy. However, this proves to be a diversion, as the unwary Finger Bearer is stabbed by Divine Dog: Totality, exorcising it and finally dispelling the domain.
The finger of Sukuna that gave the Finger Bearer its power was later consumed by Yuji Itadori unknowingly, tricked into it by Sukuna, who was inhabiting his body.
- Jujutsu Kaisen Manga: Chapter 59 (p. 13).