The connecting record
shownJujutsu Kaisen
Kenjaku killed Yuki Tsukumo in Jujutsu Kaisen.
A miniature Uzumaki blew a hole through her lower torso, and his gravity then tore her body in two at the wound. Still conscious, she turned her own technique on herself for a last attempt, piling on mass until she became a black hole meant to take him with her. He climbed out of the rubble.
What each of them is ranked on
The killer · Kenjaku · rank 3
Has worn a line of other people's skulls for something past a thousand years, most recently Suguru Geto's, and walked that face up to Gojo Satoru to shut him inside a box. Wrote the rules of the Culling Game and enrolled sorcerers in it who were given no say in the matter, then lost his head to a student who took the transplant technique off him and was wearing Gojo Satoru by the end.
statedJujutsu Kaisen · ch. 136
Kenjaku has moved his own brain from body to body across more than a thousand years.
shownJujutsu Kaisen · ch. 90
Wears Suguru Geto's body with a line of stitches running across the forehead.
statedJujutsu Kaisen · ch. 90
The stitching is explained as a brain placed inside the opened skull.
All 6 citations
shownJujutsu Kaisen · ch. 91
Closes the Prison Realm on Gojo Satoru at Shibuya station.
statedJujutsu Kaisen · ch. 143
Announces the Culling Game and the rules its enrolled players are bound by.
shownJujutsu Kaisen · ch. 243
Yuta Okkotsu severs his head.
The victim · Yuki Tsukumo · rank 25
statedJujutsu Kaisen · ch. 136, p. 1-4
Yuki Tsukumo says she is looking for a way to do away with cursed energy altogether.
statedJujutsu Kaisen · ch. 205
Star Rage is described as adding virtual mass to whatever it is applied to.
shownJujutsu Kaisen · ch. 203–208
Fights Kenjaku during the Culling Game.
What this does not settle
One death in one work. It is the only place the record puts these two in the same room, and it is evidence about that meeting and nothing wider — not a general matchup, not a rematch, and not a ranking of its own.
The ladder above it is argued from everything either of them has been shown doing; this page is argued from one citation.
Where the two disagree, the disagreement is the point, and it stays visible rather than being resolved by whichever of them happens to be on this page.