Brunhild

is the princess of Isenstein appearing in The Seven Deadly Sins: Grand Cross.

Gunnar
Nothing known about them other than the fact they loved each other and were a married couple. His death effected his wife to protect the kingdom alone.

Sigurd
They both have a rivalry due to being from opposing kingdoms. Despite that, they willingly teamed together against Meliodas. She confesses to Elizabeth that she has hidden feelings for Sigurd.

Trivia

 * Brunhild is named after the character of the same name from Germanic heroic legends.