Rasetsu

The monster effect "Return this card to the owner's hand during the End Phase of the turn it is Normal Summoned or flipped face-up" is a Trigger Effect that activates only once during the End Phase of the turn "Rasetsu" was Normal Summoned or flipped face-up. (This effect does not target.)

The monster effect "Return this card to the owner's hand during the End Phase of the turn it is Normal Summoned or flipped face-up" will not activate during the End Phase if that "Rasetsu" is in face-down Defense Position due to the effect of "Book of Moon," or if it has been sent to the Graveyard due to being destroyed by battle or card effect.

The monster effect "When this card is Normal Summoned or flipped face-up: You can reveal 1 Spirit monster in your hand, except 'Rasetsu'; target 1 face-up Attack Position monster your opponent controls, and return it to the owner's hand" is a Trigger Effect. (This effect targets 1 face-up Attack Position monster in the opponent's Monster Zone. When activating this effect, you reveal 1 Spirit monster in your hand, except "Rasetsu," as a cost.)

Even if "Rasetsu" is flipped face-up during the Damage Step due to battle, you can activate the monster effect "Target 1 face-up Attack Position monster your opponent controls, and return it to the owner's hand." (In that case, it will activate after damage calculation.)