NHF – new heroes for Heroes V 3.1.

It needs to somehow reduce the situational nature of this ability, and then it will be good, or increase its effectiveness many times over, but place it in the "_E" tier.

20% is already quite a lot. You scout the map. You see where there are human units – you attack. If they are far from the castle, you summon them using a spell that is available at the start. I don't think that the probability of getting the desired unit stack is approximately 12% is low. What is not very good is the lack of a way to empathize. Therefore, instead of diplomacy, you can give the ability to gather troops.

There are few pirates, and they are not very strong, which means they unnecessarily occupy a stack in the army, and the unit growth in cities is higher, so the loss of one or another stack is easily replenished (compared to pirates), and if you don't carry 7 different units with you, then it is better to fill the free stack by splitting up the Inquisitors/Adept, because they are casters and buffers.

With proper development, the synergy with pirates will be very strong. And these are the units that you don't mind sacrificing. And they have a good growth rate.