The apple does fall far from the tree
I haven't read the manga, so I'm not entirely sure about the details surrounding the death of the twin's mother. Please excuse any inaccuracies.
Title taken from the 31 Days theme for April 12, 2006.
Vergil's most vivid memories of his father were images of the demon knight sitting in his study, surrounded by shelves of dusty books and human oddities. The unspoken rule of their household was to never bother father when he was working, but Vergil never could help himself in his younger days. Something about his father's study entranced him — something about the mystery of the books and the way his father seemed to always be writing in a journal of endless pages piqued his curiosity. So, in spite of his better judgment and the chances of being caught and punished (or sold out by his mischievous twin brother; whichever came first), young Vergil always lingered just by the doorway, peeking through the crack, watching the tall silhouette at the red oak table writing the night away. Spying on his father in that fashion was that only way through which Vergil learned what his father's face looked like: prior to that, all he could recognize with his father's feet, which was a point on the floor that he always fixed his gaze upon in order to show his respect.
It was only after a full year of spying that Vergil's tenacity was finally rewarded: it came in the form of his father calling for him to come in without even looking up, or pausing in his writing. The ice-cold fear Vergil felt at being discovered had melted the moment his father lifted him up, set his son on his knee, and then continued to write as though he had never been interrupted. Vergil knocked at the study door the next evening, and was quietly told that he need not announce himself — a silent entrance was enough, for anything else would distract his father. Within a week he was allowed to read the books. Within a month he was allowed to ask questions. By the end of the year, he was learning spells.
When the enemies of his father attacked their home and killed his mother, Vergil had taken his brother and fled their home without looking back. He went on for years afterward, cursing the few books he had brought with him and thinking the rest were lost forever. It was only after he and Dante parted ways that he dared return to the place of his childhood. The study, he discovered, had been miraculously untouched by the flames: Sparda's magic had preserved it from entry and abuse. Undoing the bind proved ridiculously simple. Idly, Vergil wondered if looters had been stupid enough to not notice it.
Vergil lingered a moment in the doorway of the study, trying to relive the memories in spite of the hollow in his heart. And then he took his seat, opened the dusty journal on the desk, and began to read.