This strip here is arguably the crowning moment of heartwarming for the whole series. Steve (the ugly robed one) sold his soul to a demon at the age of seven (binding him to the demon's service in his plots to take over the world at a later date) in exchange for the use of a spell of prolonging life, the actual use of which is what caused his disfigured appearance. Selling his soul to that demon (and the scars that came from the event) is Steve's greatest shame; when the spell blew his face off, he immediately fled his home and didn't see another member of his family for twenty years. Now he has proven to the Spirits of Magic themselves (i.e. the stumpy guy and his currently-offscreen counterpart) that he has truly earned the chance to change the past so that he never sold his soul to use the spell in the first place and free him from the demon's control. However, (already in the past and viewing the scene) rather than change the outcome and free himself, he leads the Spirit over to the next room where his sister is laying sick with an incurable disease. As Steve says:
"This... this is my big sister Lilly. She's dying of a rare disease that only the spell I cast could cure. If the deal never happened, she would die. I... I can't put my family through that. My soul for her life. It's the fairest trade I'll ever manage"