Ragnar the Rock

"Grimmel! My old friend!"

- Ragnar to Grimmel

Ragnar the Rock was a Warlord who hired Grimmel the Grisly to kill Hiccup and Toothless in order to continue their dragon poaching operations in planning to conquer the world.

Grimmel
Ragnar appears fond of Grimmel, referring to him as an 'old friend' and implying he has worked with him on multiple counts before.

Trivia

 * Ragnar's clothing appears to be Asiatic in inspiration.