A poetic/archaic use (read たが) functioning prenominally meaning 'whose …'. Seen in poetry or classical prose.
誰が手の跡か知らず、ただ風が通り抜けた。
Whose handprint it was I do not know; only the wind passed through.
誰が命を賭して守りしものぞ、今はただ静けさのみ。
Whose life it was that was risked to protect it — now there is only silence.
A poetic expression (read たが) functioning like 'who (does/is …)'. Similar to modern '誰が〜', but archaic/literary in tone.
誰が今の世を変えんと立ち上がるか、ただ一握りの者のみ。
Who will rise to change the present world? Only a handful of people will.
誰がこの花を摘まん、遠くで鳥の声が答える。
Who will pluck this flower? The distant bird answers.