"...I see. Thank you, little one."

As Senna and Alexander descended the steps to the fourth floor, they would be able to make out a faint voice from below. The almost regal sounding voice of a male, thrumming oddly as though he was underwater.

Wrong. This is wrong. This is different. This is impossible. The only humans to have made it to the fourth floor should be the two of them, so there should not be anything present capable of speech. 

The fourth floor was a single circular room, roughly twenty meters in diameter. There were no fixtures, no items, nothing that made it anything other than a barren, impossibly lit cavern. 

The only thing present was a humanoid form in the center of the floor. Appearing as a sculpture of silver shaped in the visage of an adult male, the thing turned to face the new arrivals. Its "face", or at least what resembled a face, seemed to sneer slightly in disgust. Something that Senna and Alexander would probably notice was the presence of what was presumably the Acid Slime they had just scared off, presently coating the right hand of the silver man like a form-fitting glove. 

"...humans, turn back. You are not welcome here."

Though its mouth did not move, sounds indicative of speech reverberated out from the silver man's form. The presence he exuded was nothing short of stifling, making the atmosphere wrought by the Goblins and Slimes seem nonexistent by comparison. If it was true that the Labyrinth monsters up until this point had been unexpectedly weak, then this being was a sudden leap in quality to an absurd degree. 

"I am the Floor Guardian of this space. The Metal Slime Prince, born of the Divine Slime King, gifted the name 'Zhan' by this world's transcendent will. If you attempt to pass, I will kill you without hesitation."

Announcing his attentions coldly, the monster's body shimmered, reshaping itself slightly according to his whims. 

"Turn back, and leave this home of ours permanently. I will not attack you if you return to your own world and never return. If, however, you dare to toss aside my generosity, then you will die."

[i][center][Unique Boss-Class Monster: Metal Slime Prince "Zhan" has been discovered.][/center][/i]