Upgrade the Pepper Gun in order to kill the babies and Eyepots from a distance. Use the umbrella to block the tea attacks and knock the big enemy's charges back at him. You can now attack, dodge and repeat the process until he has been defeated. This will require some time.

Take out the Eyepots first. Lock on, get close, and when they are about to stomp, teleport backward and shoot them with the Pepper Gun. Teleport back in and slice them up while they are stunned. Repeat the process as needed. The Menacing Ruins can be defeated by knocking their fireballs back at them, then keep attacking at close range with the Vorpal Blade, teleporting in and out and side to side to avoid attacks.