If I Had a Heart (Vikings Series Opening) is written by Fever Ray under her stage name.
The song plays over the title sequence. The sequence shows a stormy sea and dead warriors, their weapon and their spoils sinking into the sea, the 9 daughters of the goddess Rán swimming around and consuming them. Figures of Norse Mythology and some of the characters from Vikings flash by. The final image shows a stormy sea, a thunderous sky and fires of a viking raid at land. Accoriding to Rama Allen, who directed the sequence: "We follow the separation of a Viking from the living. He slips into darkness amongst ornaments of his life. Weaponry, gold and bone. His fading memory flickers throughout before he is consumed by one of the Sisters. He is left a shell below the waves before we learn he is not alone, but one of many sinking below the creeping surge of Viking raiders above. A fiery massive raid assaults a darkened coast line."
The lyrics of the title theme reflects how Ragnar's endless thirst for knowledge and how mankind's greed will see to that conflicts never will cease
(Repeat verse) This will never end
Cause I want more
More, give me more
Give me more
If I had a heart I could love you
If I had a voice I sing
After the night when I wake up
I'll see what tomorrow brings
If I had a voice I'd sing
In the show of thunder, there is a single frame of Hel standing on a dark field.
In Season 4, the opening is different than the previous ones in the last three seasons, although scenes of the past opening have been used.