Elesh Norn
Legendary Creature — Phyrexian Praetor
Vigilance
Whenever a source an opponent controls deals damage to you or a permanent you control, that source's controller loses 2 life unless they pay 
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, Sacrifice three other creatures: Exile Elesh Norn, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery.
The Argent Etchings
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Enchantment — Saga(As this Saga enters and after your draw step, add a lore counter.)
I
— Incubate 2 five times, then transform all Incubator tokens you control.
II — Creatures you control get +1/+1 and gain double strike until end of turn.
III — Destroy all other permanents except for artifacts, lands, and Phyrexians. Exile this Saga, then return it to the battlefield (front face up).
Magali Villeneuve
Rulings
Elesh Norn’s triggered ability will trigger separately for each permanent dealt damage by a source an opponent controls, plus once if you’re dealt damage by that source. For example, if an opponent casts a spell that deals damage to you and two creatures you control, Elesh Norn’s ability will trigger three times. Each of those abilities will cause that opponent to lose 2 life unless they pay {1}.
(wotc • 2023-04-14)
Similarly, the triggered ability will trigger separately for each source an opponent controls that deals damage to you or a permanent you control. For example, if three creatures controlled by an opponent block and deal damage to an attacking creature you control, Elesh Norn’s ability will trigger three times.
(wotc • 2023-04-14)
Rulings
Elesh Norn’s triggered ability will trigger separately for each permanent dealt damage by a source an opponent controls, plus once if you’re dealt damage by that source. For example, if an opponent casts a spell that deals damage to you and two creatures you control, Elesh Norn’s ability will trigger three times. Each of those abilities will cause that opponent to lose 2 life unless they pay {1}.
(wotc • 2023-04-14)
Similarly, the triggered ability will trigger separately for each source an opponent controls that deals damage to you or a permanent you control. For example, if three creatures controlled by an opponent block and deal damage to an attacking creature you control, Elesh Norn’s ability will trigger three times.
(wotc • 2023-04-14)