Here the word "He" refers to Nebuchadnezzar and is a metonym for his army. Alternate translation: "His army will kill" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Possible meanings are 1) "your daughters" refers to the young women of Tyre who were working in the fields or 2) "your daughters" is a metonym for nearby towns and villages on the mainland that supported the main city of Tyre. See how you translated a similar phrase in [Ezekiel 26:6](./06.md). Alternate translation: "your daughter communities who are on the mainland" (See: [[rc://en/ta/man/translate/figs-metonymy]])