It's a war song. Created during Yugoslav wars by "HOS"
The HOS stands for 'Hrvatske Obrambene Snage", which means Croatian Defenders.
It originates from ww2 when Germany occupied Yugoslavia, Germany created Croatian puppet state known as "NDH" - Nezavisna Hrvatska DrΕΎava, or Independent state or Croatia. They were one of the closest ally to Germany and yes, they were killing Jews but also Gypsies and Serb too.
The song describes patriotic people willing to avenge Ante PaveliΔ and other know NDH-imortant people. It talks about being proud of it and for killing Serbs, at the end, it talks about how Serbs will say "Long live NDH!".