Why are they here?

Are they actually the two legendary Triple-Zeros?

And they seem to be following Shinsen...

Shinsen remained silent, and gestured to Johnny with his hand.

Johnny drew a revolver out from the inner pocket of his suit, rolled
it around his fingertips, and placed it on Shinsen's right hand.

Shinsen took the pistol and approached Nanamura.

Is he going to shoot—?

Nanamura couldn't move, his knees were trembling.

"N-no, it can't be... how is this possible..."

Shinsen turned the gun grip towards Nanamura and handed it to
him.

At this point, Nanamura must have understood everything with
his ‘Allegro Agitato’ thinking speed.

He took the gun with a trembling hand.

"Right... this means... the fall has already begun..."

Nanamura whispered this and pulled the trigger at his temple.

He immediately turned into a corpse and collapsed in front of the
main entrance of the Norman’s Hotel.