If a "Black Luster Soldier" monster is Ritual Summoned using 2 copies of this card, it will not gain 2 copies of each effect granted by this card. However, if a "Black Luster Soldier" is Ritual Summoned using both this card and "Evening Twilight Knight", it will gain the 4 effects granted by those monsters: 2 copies of the monster-banishing effect, and the other 2 unique effects (1 from this card, and 1 from "Evening Twilight Knight").
The "● When this card destroys an opponent's monster by battle and sends it to the Graveyard: You can activate this effect; this card can make a second attack in a row." effect is a Trigger Effect. (It does not target. It can be activated at the end of the Damage Step when the opponent's monster is destroyed by battle and sent to the Graveyard.)