His death may be the work of some unknown enemy.

"But what if one of them is this unknown enemy?"

After all, these men might have been hired by her unknown enemy.

Oh, yes, this unknown enemy must be made to pay.

Now, here we are on a planet with an unknown enemy.

His unknown enemies had found him once again, and it was time to run or die.

"Suppose force had been necessary, on the part of my unknown enemy!"

He sensed a new move by his personal and unknown enemy, the Light.

He hadn't been working, fighting all these years, to sacrifice himself without good reason, to an unknown enemy.

"What do you think was the ultimate purpose of this unknown enemy from the north?"