A new more important slave is going to join Ragnar (Travis Fimmel) in his raids.
"Vikings" season 4 spoiler revealed there is a new slave coming in, as well as two new vikings that will join the king of Kattegat.
"Then we have Yidu (Dianne Doan), a Chinese slave captured in the Red Sea," Michael Hirst told The Hollywood Reporter when asked for "Vikings" season 4 spoilers on new characters.
"Who knew the world was small enough even then for people captured by pirates in the red sea might to end up in Frankia, and then in Scandinavia? But I checked with our historical consultant and he said it's all possible, it's all plausible, it almost certainly happened."
Yidu will probably replace Althestan who was killed off last season. This monk is arguably the biggest, most shocking omission in the third season of History Channel TV series "Vikings." George Blagden's character transformed from a slave into a good friend for Ragnar who in effect feels alone now.
The two other characters are King Harold Finehair (Peter Franzen) and his brother Halfdan the Black (Jasper Paakkonen) who Hirst said will play an integral role in Northmen's conquest.
"They come on board because they want to go raiding with Ragnar to Paris," he said.
"But of course they have ambition -- all Vikings worthy of their name were ambitious for fame -- and so that becomes an issue."
Another "Vikings" season 4 spoiler from International Business Times teased Yidu's character looks so special to everyone in Kattegat that even the king will be captivated by her.
"The people of Kattegat have never seen someone like her, from her looks, to views on the world and beliefs," the actress told IBTimes.
"But perhaps it's that very same mystery, which frightens villagers, that will ultimately peek Ragnar's interest."
IB Times further wrote, quoting Doan:
"According to Doan's character description, the inquisitive -- and very sick -- king will immediately become captivated by the exotic outsider, which will begin his journey uncover more about Yidu's past."
For more "Vikings" season 4 spoiler, click here.