This is the 10148th most frequent Polish word.
bohaterze
"Hero" (vocative case in Polish).
Here, 'bohaterze' is the locative form of 'bohater', used as part of the prepositional clause 'o dzielnym bohaterze' (about a brave hero).
Opowieść mówi o dzielnym bohaterze, który ocalił wioskę.
The tale speaks of a brave hero who saved the village.
In this sentence, 'bohaterze' seems to appear due to a conjugation error; the correct word should be 'bohatera'. The mistake highlights the importance of proper case usage in Polish.
Zawsze marzyłam, aby poznać bohaterze z tej legendy.
I've always dreamed of meeting the hero from that legend.
The word 'bohaterze' is again in locative case here, indicating the topic of conversation in relation to the use of the preposition 'o' (about).