The connecting record
shownOverlord: The Dark Warrior
Ainz Ooal Gown killed Clementine in Overlord: The Dark Warrior.
in his true form, crushed in an embrace in E-Rantel's cemetery
What each of them is ranked on
The killer · Ainz Ooal Gown · rank 1
Momonga — the Sorcerer King
Killed Shalltear Bloodfallen, a level-100 built as a counter to everything he does, by planning the fight before it began: a super-tier opener, a bluff about mines laid in the air, and a guildmate's white armour worn through [Perfect Warrior] once her mana ran low — dropped at the end for the super-tier spell that killed her. Nothing else he fights is numbered near him. A Frost Dragon Lord dies to a single [Grasp Heart]; the Elf King, his mana gone against walls of skeletons, runs once Ainz has destroyed his Behemot; and at Katze Plains one super-tier spell kills seventy thousand men in seconds before the five Dark Young it calls up start on the rest.
shownOverlord: The Bloody Valkyrie · vol. 3, ch. 4
Opens the fight against Shalltear with the super-tier spell [Fallen Down].
shownOverlord: The Bloody Valkyrie · vol. 3, ch. 5
Fights the last stretch in Touch Me's armour, wearable through [Perfect Warrior].
shownOverlord: The Bloody Valkyrie · vol. 3, ch. 5
Casts off [Perfect Warrior] and kills Shalltear with the super-tier spell [Fallen Down].
All 8 citations
statedOverlord: The Bloody Valkyrie · vol. 3, ch. 5
Reckons himself, as a level-100 magic caster, about the equal of a level-33 warrior; [Perfect Warrior] makes him a level-100 warrior whose stats far outstrip Shalltear's, since she is not a pure warrior.
shownOverlord (anime) · S01E13
Appears in Touch Me's silver armour and cuts Shalltear across the chest.
shownOverlord: The Dwarven Crafter · vol. 11, ch. 5
Kills the Frost Dragon Lord Olasird'arc Haylilyal with one [Grasp Heart].
shownOverlord: The Caster of Destruction · vol. 9, ch. 4
Casts Iä Shub-Niggurath on the Royal Army's left wing and sets five Dark Young on the rest.
shownOverlord: The Half-Elf Demigod Part II · vol. 16, ch. 5
Lowers his walls of skeletons and destroys the Elf King's Behemot with [Cacophosus Burst].
The victim · Clementine · rank 19
Four adventurers of the Swords of Darkness died to her during Nfirea Bareare's kidnapping. Then she met Momon in E-Rantel's cemetery and landed a martial-arts strike to his head that would kill nearly anything in the New World. It did nothing: the man inside the armour was Ainz, whose passive immunity voids attacks from far enough beneath him. He revealed himself as Ainz and crushed her in an embrace in his true form.
shownOverlord: The Dark Warrior · vol. 2, ch. 4
Kills the four members of the Swords of Darkness while kidnapping Nfirea.
shownOverlord: The Dark Warrior · vol. 2, ch. 4
Lands a strike to Momon's head that leaves him unhurt.
statedOverlord: The Dark Warrior · vol. 2, ch. 4
Ainz has a skill that invalidates attacks from opponents far below his level.
All 4 citations
shownOverlord (anime) · S01E09
Ainz crushes her body with both arms.
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.