The connecting record
shownJujutsu Kaisen
Megumi Fushiguro killed Reggie Star in Jujutsu Kaisen.
The player he opened the unfinished domain on.
What each of them is ranked on
The killer · Megumi Fushiguro · rank 13
Called Mahoraga in Shibuya knowing what the shikigami does to a summoner who cannot bring it to heel, and said while doing it that he did not expect to be alive when the summoning finished. Against the finger bearer earlier he had refused that same summons and opened his own domain instead — the one he calls unfinished, and which he opened again on a Culling Game player later regardless.
statedJujutsu Kaisen · ch. 171
Megumi states that his Chimera Shadow Garden is incomplete.
shownJujutsu Kaisen · ch. 170
Opens Chimera Shadow Garden against Reggie Star in the Culling Game.
statedJujutsu Kaisen · ch. 117
The Ten Shadows Technique is said to kill any user who fails to subdue Mahoraga.
All 6 citations
shownJujutsu Kaisen · ch. 58
Declines to summon Mahoraga against the finger bearer and opens his incomplete domain instead.
shownJujutsu Kaisen · ch. 117
Summons Mahoraga in Shibuya against Haruta Shigemo.
statedJujutsu Kaisen · ch. 117
Says he does not expect to survive the summoning.
The victim · Reggie Star · rank 28
statedJujutsu Kaisen · ch. 170
Reggie Star's cursed technique turns a receipt into the object the receipt was written for.
shownJujutsu Kaisen · ch. 171
Produces a car out of a receipt during his fight with Megumi Fushiguro.
shownJujutsu Kaisen · ch. 172–173
Megumi Fushiguro kills him in 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.