The death of fan translation for anime has me missing TL notes that might have explained what the fuck Senjumaru or Ichibe's Bankai names mean, but what they do is pretty obvious. Senjumaru's is like a domain expansion from Jujutsu Kaisen where she traps you in some kind of themed murder, and Ichibe's just lets you directly overwrite someone's identity and destroy them on a conceptual level.