How has stevenson used language to create suspense in the opening of the chapter?

Stevenson uses Utterson to relate a story to Enfield. Utterson is lawyer, he has an air of credibility, who has seen men go down a dark path. There is a sense of foreboding and mystery that Stevenson uses to set the reader up for the dark tale he will unfold.

In this character, it was frequently his fortune to be the last reputable acquaintance and the last good influence in the lives of downgoing men. And to such as these, so long as they came about his chambers, he never marked a shade of change in his demeanour.