Venom seeks revenge on Nova for harming his sister, Mary Brock. This is the only mention of Mary outside of Venom: Dark Origin (2008) and the latest issue of Venom, issue 9 (2018).
From Nova (1999) #3, #6, and #7
The Amazing Spider-Man: Venom Inc. ALPHA #1 variant by Jamal Campbell from Fried Pie Comics
Venom swears vengeance on Nova for bringing harm to his sister, Mary Brock.
From Nova #6 (1999)
Venom sprouts wings to secure a safe landing.
From Nova: The Human Rocket #7 (1999)