These two men were the big bosses of the famous pirate group in Owari, the "Kawamata Group." Before Oda Nobunaga became the Family Head, he often hung out with them—he learned iron cannon skills from them, exercised by swimming together, and even in the ninja squad formed by Nobunaga, many members originally came from the "Kawamata Group."
Now that Nobunaga's territory had expanded and his control over the Kawamata region grew stronger, the "Kawamata Group" had fully sided with the Oda Family. Hosokawa Shigekatsu, Maeno Nagakane, and others officially became Nobunaga's personal attendants—of course, they'd been considered retainers before, but as vassal retainers, the kind of household retainer that comes from local powerful clans submitting to the daimyo; they weren't really Nobunaga's direct forces, or even the Oda's forces at all. After all, these frontier clans had always played both sides and were common retainers of both the Oda and Saito families.