With his twisted foot on a wooden block, Engstrand is the cloven-hoofed devil character Ibsen loved to write. He's similar to Krogstad in A Doll's House. When we see him being honest, he's unapologetically unreformed, even gleefully so. With a wink in his eye, he tut-tuts his own drinking to Regina: "Yes, we're weak vessels, we poor mortals, my girl…and temptations are manifold in this world, you see" (1.10-12). She sees through him and his "fatherly" invitation to work the Sailor's Home. Regina is too much like him not to understand his schemes.
The Pastor, however, is susceptible to Engstrand's explanations, apologies, and promises to try to improve himself. Much of the comic material in the play comes from watching Engstrand manipulate the gullible Pastor. Engstrand is constantly breaking himself down to build the Pastor up. The coup d'état (a sudden, decisive move of power) is at the end of Act 2, when Engstrand convinces the Pastor to hold a prayer service at the Memorial. When Engstrand enters, the Pastor is in an angry tizzy over the carpenter's sham marriage with Johanna, which he performed. By the end of the scene, however, the Pastor is wound around Engstrand's finger even tighter than before, and feeling that he owes Engstrand something:
MANDERS. Yes, assuredly. And I do it with all my heart. Forgive me for misunderstanding you. I only wish I could give you some proof of my hearty regret, and of my good-will towards you –
ENGSTRAND. Would your Reverence do it?
MANDERS. With the greatest pleasure.
ENGSTRAND. Well then, here's the very chance. With the bit of money I've saved here, I was thinking I might set up a Sailors' Home down in the town. (2.183-186)
More single-minded and determined than Mrs. Alving, Engstrand has been working for that Sailor's Home since the beginning of the play. And now he'll get it. Without a doubt, Engstrand is the most triumphant character in the play.
The Sailor's Home is the repository of sex in the world of the play. Pushed out of the home by the life-denying, strict morals that guide Pastor Manders, Mrs. Alving, and their whole community, there's nowhere for sex to go but somewhere dirty and foreign. Engstrand recognizes that reality and won't hesitate to make a buck off of it.