According to 1 Chronicles 18:12, who struck down 18,000 Edomites in the Valley of Salt?

Answer: Abishai son of Zeruiah

1 Chronicles credits Abishai, Joab's brother, with striking down 18,000 Edomites; David then put garrisons in Edom.

“Moreover, Abishai son of Zeruiah struck down eighteen thousand Edomites in the Valley of Salt. He placed garrisons in Edom, and all the Edomites were subject to David. So the LORD made David victorious wherever he went.”— 1 Chronicles 18:12-13 (BSB)