Sägehorn-Nemesis

Sowie die Sägehorn-Nemesis ins Spiel kommt, bestimme einen Spieler.
Falls eine Quelle dem bestimmten Spieler bzw. einem Permanent, das jener Spieler kontrolliert, Schaden zufügen würde, fügt sie ihm stattdessen doppelt so viel Schaden zu.

Némésis aux cornes dentelées

Au moment où la Némésis aux cornes dentelées arrive sur le champ de bataille, choisissez un joueur.
Si une source devait infliger des blessures au joueur choisi ou à un permanent qu'il contrôle, elle inflige le double de ces blessures à la place.

鋸角の宿敵

鋸角の宿敵が戦場に出るに際し、プレイヤー１人を選ぶ。
発生源１つがその選ばれたプレイヤーやそのプレイヤーがコントロールしているパーマネント１つにダメージを与えるなら、代わりにそれはその２倍の点数のダメージを与える。

Sawhorn Nemesis

As this creature enters, choose a player.
If a source would deal damage to the chosen player or a permanent they control, it deals double that damage instead.

Modern Horizons 3 Commander

As Sawhorn Nemesis enters the battlefield, choose a player.
If a source would deal damage to the chosen player or a permanent they control, it deals double that damage instead.

The protector of a battle with the Siege subtype is not that battle's controller.

If another effect (or effects) modifies how much damage a source would deal to the chosen player or a permanent they control (for example, by preventing some of that damage), the player being dealt damage or the controller of the permanent being dealt damage chooses the order in which any such effects, including the effect of Sawhorn Nemesis, apply. If all of the damage is prevented before Sawhorn Nemesis's effect would apply, its effect no longer applies.

If damage dealt is being divided or assigned among multiple permanents or players, that damage is divided or assigned before any effects that modify how much damage will be dealt. For example, if you attack the chosen player with a 5/5 creature with trample and it's blocked by a 2/2 creature they control, you can assign 2 damage to the blocker and 3 damage to the defending player. Those amounts are then doubled to 4 and 6, respectively.

The damage is dealt by the same source as the original source of damage. The doubled damage isn't dealt by Sawhorn Nemesis unless it was the original source of damage.