Trouble Quest is a virtual game originally developed by Lala Satalin Deviluke but she abandoned and forgotten about it. Later, Lala's little sister Momo developed it further and finally completed it before using it to test Rito Yuuki if he's worthy to be Lala's fiance or not. In the PlayStation Vita game To LOVE-Ru Darkness: Battle Ecstasy, Rito has to travel to an upgraded version of the game called "Trouble Quest 3".