His maternal grandfather was the politician Vladan Đorđević, who had served as the Prime Minister of Serbia and the mayor of Belgrade during his long career[2] and who was of partial Aromanian descent from the region of Macedonia.

[3] One of Jovan Deroko's great-grandfathers was a Venetian by the name of Marco de Rocco, who moved to Dubrovnik and married a local woman.

[4] Deroko's division was stationed on the periphery of Zagreb at the same time Croatian officers were massively leaving the Yugoslav side.

The Wehrmacht entered Zagreb without battle and Deroko retreated towards Montenegro in order to escape imprisonment.

In the middle of June, Deroko arrived at Ravna Gora and quickly made himself known as one of the most capable commanders and became known as the youngest captain in the entire Chetnik organization.

The failed siege of Kraljevo also marked the beginning of the civil war between Partisans and Chetniks.

After the Chetnik attack on Užice on 1 November 1941 (known as the Battle of Trešnjica), Deroko gained new functions.

Deroko then attacked a new area of Ljubić with his cannons with the aim of bombing Čačak which was held by Partisans.

Deroko took control of the area on the surrounding hills beside a small lake from which he had a good view of the situation.

In trying to stop the Partisan unit which was advancing upon the hill however, Deroko was killed beside his cannons when struck in the head.