The phrase 'おっと 誰か 来たよう だ' carries a sense of sudden awareness mixed with caution. In English, it could be translated as 'Oh, looks like someone's coming' or 'Hmm, seems we've got company.' The key is capturing that moment of realization where the speaker notices an approaching presence without being overly dramatic.
Translating anime-style dialogue often requires balancing literal meaning with cultural nuance. A more casual version might be 'Whoa, someone's here,' while a suspenseful context could use 'Wait... I hear footsteps.' The English dub of 'Death Note' handled similar lines by emphasizing tension, whereas 'Spy x Family' opts for lighter phrasing to match its tone.
Interestingly, the particle 'ようだ' adds speculation, so translations like 'I think someone arrived' work too. It depends whether you prioritize accuracy or natural flow—localization isn't just word substitution but adapting the scene's vibe.