Since demand concession casus belli will cost less than 5 infamy (unless the justification is discovered on day 1), it is beneficial to annex a province with foreign cores and release said nation as a puppet.This is unlimited, but at the cost of 5 prestige. If their puppets are in their own sphere(for example, Lucca in Italian sphere) than the event will make the formable countries annex them free. Germany and Italy can release puppets to reduce the infamy.It is however at the cost of 5 prestige per nation released. Sweden can release Norway and Jan Mayen just before it forms Scandinavia Prussia can release Danzig before forming the North German Federation NGF can remove an insane amount of infamy while forming Germany. A formable country can release a nation in the same culture group just before it forms the nation and annexing it again.A great power can sphere Colombia, build The Panama Canal which annexes a single province, and release Panama as a vassal.There are several 'gamey' ways to reduce infamy: Great War: While in a great war, infamy costs for the 'justify war' function are reduced to 33%.(This can be modified in the static_modifers.txt file) POP Consciousness: When above 1.0 in the nation, this creates a modifier of +0.01 consciousness.There are also several events and decisions that increase or decrease infamy. These costs only occur outside of the Casus belli system, which determine infamy gains from the justify war action. The Acquire state casus belli costs up to 11 infamy

Victoria 2 infamy cheat