Mirhab

“'Ali chanted in reply: I am the one whose mother named him Haidar, (And am) like a lion of the forest with a terror-striking countenance. I give my opponents the measure of sandara in exchange for sa' (i. e. return thir attack with one that is much more fierce). The narrator said: 'Ali struck at the head of Mirhab and killed him, so the victory (capture of Khaibar) was due to him.”

Hadith reference: Sahih Muslim 1807a (sunnah.com), from Salamah ibn al-Akwa RA. The report crediting Ali RA.

“فقال رسول الله صلى الله عليه وسلم: من لهذا؟ قال محمد بن مسلمة: أنا له يا رسول الله، أنا والله الموتور الثائر، قتل أخي بالأمس؛ فقال: فقم إليه، اللهم أعنه عليه ... ثم حمل مرحب على محمد بن مسلمة، فضربه، فاتقاه بالدرقة، فوقع سيفه فيها، فعضت به فأمسكته، وضربه محمد بن مسلمة حتى قتله.”

al-Sirah al-Nabawiyyah 2/333-334, Ibn Ishaq from Jabir ibn Abd Allah RA, "maqtal Mirhab al-Yahudi" (islamweb library). The report crediting Muhammad ibn Maslamah RA.

“قَالَ وَبَرَزَ لَهُ عَمِّي عَامِرٌ فَقَالَ قَدْ عَلِمَتْ خَيْبَرُ أَنِّي عَامِرٌ شَاكِي السِّلاَحِ بَطَلٌ مُغَامِرٌ قَالَ فَاخْتَلَفَا ضَرْبَتَيْنِ فَوَقَعَ سَيْفُ مَرْحَبٍ فِي تُرْسِ عَامِرٍ وَذَهَبَ عَامِرٌ يَسْفُلُ لَهُ فَرَجَعَ سَيْفُهُ عَلَى نَفْسِهِ فَقَطَعَ أَكْحَلَهُ فَكَانَتْ فِيهَا نَفْسُهُ ‏.‏ قَالَ سَلَمَةُ فَخَرَجْتُ فَإِذَا نَفَرٌ مِنْ أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم يَقُولُونَ بَطَلَ عَمَلُ عَامِرٍ قَتَلَ نَفْسَهُ ... قَالَ ‏"‏ كَذَبَ مَنْ قَالَ ذَلِكَ بَلْ لَهُ أَجْرُهُ مَرَّتَيْنِ ‏"‏ They exchanged blows. Marbab's sword struck the shield of 'Amir who bent forward to attack his opponent from below, but his sword recoiled upon him and cut the main artery: in his forearm which caused his death. ... He said: He who has passed that remark has told a lie, for 'Amir there is a double reward.”

Sahih Muslim 1807a (Book 32, Hadith 160), Kitab al-Jihad wa al-Siyar, Salamah ibn al-Akwa RA's long narration of Hudaybiyyah, Dhu Qarad and Khaybar (sunnah.com). Amir died of his own rebounding sword.