What is the meaning of たれ?

: interrogative personal pronoun; who

垂れ: sauce, gravy

imperfective and stem (or continuative) forms of たれる (tareru) [ichidan]

hypothetical and imperative forms of たる (taru) [godan]

hypothetical form (仮定形) and imperative form (命令形) of たり (tari) [r-irregular]

Source: wiktionary.org