Long ago, Knull wielded a mighty blade known as All-Black, the Necrosword. It was said that he had once used the weapon to strike down a Celestial — one of the oldest and most powerful cosmic entities in the known universe. Stories claim that Knull triumphed, but that the Necrosword was lost in the fray.
— Venom's In-game Lore
Knull is featured as a non-playable character in the game Marvel Rivals.
Lore[]
According to symbiote legends, Knull had wielded the mighty blade known as the All-Black/Necrosword. He had used it to strike down a Celestial, however losing it in the fray. [1]
Knull created all of the symbiotes, including Venom and made the planet Klyntar their home. At some point he interacted with Hela, the two became enemies and Hela warned Knull to stay away, it is because of this Venom believes Knull will come for her.
When the Guardians of the Galaxy were stranded on Klyntar during a scouting mission and left fighting for their lives against hordes of symbiotes, Knull took notice of Groot and believes his regenerative powers are the key to creating the ultimate symbiote.