Alvaro Pizarro also known as "Corrupt King" is one of the criminals who was given life sentence in the 6th level of Impel Down. After Infiltration of Luffy and Blackbeard in Impel Down, he has now been Freed By Marshal D.Teach also known well as Blackbeard and has since joined Blackbeard Pirates By becoming one of Blackbeard's Commander. Alvaro Pizarro seems to be a very unique and interesting character in one piece story line. Alvaro Pizarro also has horns like Kaido, Moria and many other pirates in one piece. Alvaro Pizarro is an interesting character as nothing related to his bounty and his powers have been revealed to us yet. He seems to be a powerful guy as he was imprisoned in 6th level of Impel Down. The prisoners in 6th level of Impel Down were the worst criminals in one piece story line that were capable of destroying a country on their own as mentioned by Previous Fleet Admiral Sengoku.

I believe Alvaro Pizarro is based on "Francisco Pizarro" who was a Spanish conquistador who led an expedition that conquered the Inca Empire. He captured and killed Incan emperor Atahualpa and claimed the land of Spain. I think Oda got inspiration from "Francisco Pizarro" and Created Alvaro Pizarro Character. Since he belonged to a Royal Family he is not wearing a criminal outfit as other levels 6 prisoners in Impel down. According to my theory, I also believe that Alvaro Pizarro was the Right-hand man and also one of the three Natural calamities of Yonko Kaido. Calamities of Kaido have been based on cards like first calamity Jack is based on "jack" of card similarly someone is based on queen and Alvaro is based on "king" from cards. I also believe that at one point of time he betrayed Yonko Kaido and that made Kaido really upset to a point that Kaido wanted Pizarro dead. Maybe that's the reason why Kaido was captured by marines numerous times and was death sentenced so many times even though he is powerful. Kaido must have tried infiltrating and killing Pizarro many times which lead to Kaido being Captured by Marines Several Times. Alvaro Pizarro also has many similarities to Yonko Kaido's Beat Pirates as he has Horns Just like Kaido and Jack of Beast Pirates. I also believe that Alvaro Pizarro has been given the title of "Corrupt King" as he killed the previous Shogun of Wano Kuni just like "Francisco Pizarro" who captured and killed the Incan Emperor Atahualpa and claimed the land of Spain. The Horns of Alvaro Pizarro and him not wearing a criminal dress even though being criminal from 6th level prisoner of Impel down led to the conclusion that he was indeed a member of the Beast Pirates.

I believe that there is a race in OnePiece that has people having horn just like other race such as Giant race, Mink race etc. I believe so as there are lot of characters that have been introduced to us having horn such as Pizzaro himself, Kaido, All other Members of Beast Pirates, Gecko Morria etc. Hence, This just indicates the presence of such a tribe like other tribes present in onepiece story line.