Paradox developer marijn211 published a new Hearts of Iron IV dev diary on 3 November 2026, walking through parts of the upcoming Romania focus tree. The post covers the left-hand side of the tree, both in terms of in-game layout and political direction, plus a closer look at the cooperation mechanic first teased in an earlier dev corner.
The cooperation mechanic lets Romania interact with neighboring countries by investing political power into tiers, similar to how an industrial concern works. Each tier is cheap to unlock but needs upkeep to keep its bonuses, and higher tiers unlock extra decisions. Relations with Hungary and Bulgaria start locked off, reflecting real historical tension, and players need specific focuses or a shared faction to open them up.
Military branch
Romania starts in 1936 with almost no military production, something reflected by a national spirit that improves as players complete military focuses. That ties into the historical Ten-Year Modernization Program pushed by figures like Ion Antonescu in 1935.
The naval branch leans on the real expansion of the Galati Shipyards, with alt-history options to grow Romania’s river fleet instead of building blue-water ships, since vessels of that size aren’t represented in-game. The air branch follows the development of the IAR 80 fighter, with branching choices to stick with cheaper but outdated Polish-designed planes or push into jet engine research alongside Henri Coanda. The center of the tree focuses on building up arms production and tank manufacturing, including buying small numbers of foreign tanks for research bonuses, while the right side handles doctrine and organization.
Communist and democratic paths
The communist branch includes the tree’s only civil war, a three-way, optional conflict that can also be avoided by winning power democratically. Players choose between two factions: the Soviet-aligned “Prison Faction,” run by imprisoned leaders infiltrated by NKVD agents, and a Stalinist group with looser Soviet ties. This path also adds a people’s militia mechanic where weapons, not increased conscription, are spent to arm reserve divisions.
The democratic branch lets players sideline King Carol, hand the throne to his son Michael, and tackle corruption tied to incidents like the Škoda Affair. Diplomatic choices include aligning with the Allies or reinforcing the Little Entente, with bonus rewards for winning wars while keeping casualties low.
Paradox said the next dev diary, the final one for this DLC, will cover art and achievements.
What this means for mod users
Players running Hearts of Iron IV mods, especially overhauls or alternate-history scenarios touching the Balkans, should expect the Romania DLC to shift focus tree balance once it releases. It’s a good idea to back up save files and check mod update logs before loading a campaign that uses Romania heavily, since new mechanics like the cooperation system could conflict with existing country rework mods.
Source: Steam · Image: Steam
