Last Roman Campaign: Ostrogothic Kingdom Legendary Difficulty(with spoiler)

Here are several tips for other players who are interested in this DLC and faction. Because the campaign has certain scripted content, so if you don't want spoiler, please do not continue to read.

Ostrogothic's best friend is Visigothic kinsmen. Do not mess up with your neighbor. In the first turn, I advise to marry our daughter to their heir and take their daughter as our heir's wife. Although Visigoths occupies the city Massilia, don't try to get the whole Provence province to attack them. Later on, Franks will grow quite unfriendly toward us. If we have Visigothics to secure on flank, it will be very helpful.

At the beginning, we have another friend, Vandals. To be honest, it is a helpless friend which is doomed to perish because in Turn 1, it already has two enemies, Sardinia and Belisarius. Even if it can beat Belisarius, the scriped Moors invasion will certainly weaken it, which gives Berbers to its west opportunity to declare war on Vandals and annex its territory. Feel free to declare war on Vandals or offer treaty to join the war against it.

For Belisarius and Roman Empire, I keep restraint not mess up with them too early. In my latest playthrough, Belisarius triumphed in his North Africa expedition and then came to Italy to raid. I didn't declare war on him for his raid penalty on my public order. I waited for a later, better time to deal with him(You will see below).

Frank is my first antagonist. As long as it succeeded in war with Burgundians, it has high chance to declare on Ostrogoths no matter what. Get prepared.

In Turn 1, you have a vast kingdom, Italy and Sicily, and a small portion of Dalmatia and Provence. However, the economy is very weak and the public order is pathetic. And you have five armies.

Because the public order is pathetic, the best way I find is just to slide our tax to the highest rate. Forget about the public order. Let the separatists rise. Because we have five small and capable armies(very good scholae cavalry), rebels are not a thing. Besides, the rebels at the early stage do not emerge with large forces, usually three units. Even your garrison could fend off the attack of the separatists. Yes, you have to be busy early on to move your armies in your kingdom to put out the rebellion. However, the good thing is you have enough money to accelerate your building process comparing with normal tax rate.

When you are busy killing rebels and building your kingdom, the two crucial buildings are cattle farm and great theater.

Why cattle farm? Because later on, the volcano eruption(spoiler) will degrade the fertility of the lands. So its better to have cattle rather than wheat because less impact on food amount. Plus more money from cattle.

Great theater is our only building can offer highest public order buff in a single building. Since legendary difficulty has -8 public order penalty, build them and build more.

When shall we go back to normal tax rate? I think it is when you think growth is more important. I suggest you can slide tax rate back when you have 10k income every month under normal tax rate. The quick population growth can give you more slots to build.

This is scripted content. In my playthrough, seven full stacks appear in north Italy in the mid of 540(In lower difficulty, maybe fewer stacks appear). The good thing is that I already destroyed Frankish Kingdom. The last several region I annexed through "Join Empire" diplomacy option. Leave several armies to quench the rebels in your newly conquered Frankish lands. Move your best armies to the north Italy. I moved four of my best full stacks plus a half stack army in Dalmatia. Don't worry. Even fewer than the enemy, they will be defeated at last although I lost a city temporarily. Don't dream to be peace with them although they instantly are at war with Romans. They will declare war on you no matter what.

Not long after Longobards invasion, another scripted event will happen. Justinian Plague. Actually, I am happy with the Plague. With the help of my Great Theatre, my provinces' public order is manageable. The good thing is, Belisarius who raided my land for a long time, will finally be dealt with, once for all. Because of the plague, his armies are weakened, losing significant amount of men. And AI's Belisarius armies will not upgrade themselves. You won't have any difficulty to destroy this faction.

What about our own armies? Well, if your armies are on the land, they may catch plague as well. But if you move your army at sea... I think it's a trick to keep your army strength and waiting for your target to be weakened.

Now, at this stage, even the legendary difficulty is nothing. Declare war on Justinian, destroy his garrision armies along the coast. Although they are full stack, their quality is very poor. Frankly, this accurately depicted the Limitanei's role in Roman Empire. Destroy them, get the whole Dalmatia, victory is yours.