You can activate
"Trojan Blast" when a face-down monster shifts, such as with
"Creature Swap". But no damage will be inflicted because it was face-down.
You cannot activate
"Trojan Blast" when a monster shifts control to become an Equip Card. So you cannot activate
"Trojan Blast" when
"Relinquished" or
"Allure Queen" equips itself with your monster.
"Trojan Blast" is not a targeting effect. Select the monster when
"Trojan Blast" resolves.