There's something electrifying about how Japanese animation captures intensity in its characters' expressions. When a protagonist in 'Demon Slayer' unleashes their signature move, that fierce determination radiating from their eyes and posture – that's what we call 'kenmaku'. Translating it directly as 'sword aura' feels too literal, but 'battle fervor' might come closer to capturing the spirit.
English tends to separate physical and emotional states where Japanese blends them. You'd say someone is 'glaring daggers' when angry, or describe a warrior 'burning with fighting spirit'. The closest single-word equivalent could be 'vehemence', though it lacks the visual component. Anime fans might recognize 'killing intent' from subtitles, but that's more 'satsui' than 'kenmaku'. Perhaps we need to borrow the term like 'samurai' or 'tsunami' – some concepts transcend translation.