Eira Haddock

Hiccup
Hiccup is Eira's brother whom she was separated at birth. while she was raised by her father, Hiccup was raised by Dragon Hunters, especially by Viggo and Ryker. Unlike Sigrid and Eira who got off on the right start, their relationship was strained. After learning she was his sister he disowned his adoptive family.

SnotIout
Snotlout's rather protective of Eira, despite her being strong enough to wield an ax. To put it one way, he threatened to break every bone in Eira's boyfriend, Liam.