Mr. Rosso is an acquaintance of Nina Fortner. He is a former hitman and currently owns a restaurant. He employed Nina as a waitress there and Anna's radiance and beauty gathered many customers who flocked his restaurant.
Rosso was a troubled youth growing up. It all began with blackmail and then stretched out to robberies, and eventually, murder. He became a hitman, and a world class one at that. Killing people didn't matter to him -- it was just his job; there was no feeling behind it. He rewarded himself by eating very well, but no matter how rich the food, it seemed utterly tasteless to him.
One sunny afternoon, he was to execute a man who was eating at an outdoor cafe. It was like any other day, and at this point he couldn't even remember how many people he killed. As he watched, ready to pull the trigger, his victim-to-be was having a coffee. He put exactly five spoonfuls of sugar in it, then drank it. At that instant, something clicked inside Rosso. He just couldn't bring himself to kill that man. No, not that man who was enjoying his coffee so much; he knew it was wrong to take away that simple pleasure. That day, he could finally taste his meals...finally understand the taste of sugar, so he hung up his gun for good.
His personality changed drastically after that day, and he opened up an Italian restaurant called "Rosso's Restaurant." He employed Nina Fortner, who was using the name Anna Liebert. The two got along great, and her looks really helped him boost his business. One day, she began asking him if it was okay for her to leave for a few hours during the afternoon. Naturally, he agrees, but grows curious and asks her where she goes every day. Anna tells him she's learning how to shoot a gun, and then asks Rosso if he's ever fired one, to which he responds by saying no, and that just looking at guns makes him nervous.
Although they refrain from saying anything, the two are both very aware of each others' pasts: Anna knows he's a hitman, and Rosso knows that she disappeared after her parents were murdered two years ago. Eventually they confront each other on these matters, after which Anna has to leave. Rosso sees her off at the Frankfurt Central Station and, right before the train doors close, tells her that it's easy to kill if only she can forget the sweetness of sugar.
Mr. Rosso is a jolly man with good humor. He always puts five sugars in his coffee, and loves to see Anna's smile as he does that. He loves movies, and regrets not having enough free time to watch them when he was younger. Among his favorites is a film entitled "Summertime," which always makes him teary-eyed.
"Killing's easier than you think; you just have to forget how sweet the sugar is."
"Anything worth learning takes practice."
- When he was training Nina to cook a pasta dish, he said pasta dish is not a pasta dish when you cannot taste every ingredient you put in.