Tae-jun Kan

Kang Tae-jun is the second son of the Fire General Gang Soo-jin.

[Spoiler] He is in love with Yona and has been determined to make her his wife so he could inherit the throne of Kouka Kingdom in the beginning; however, his "plans" were thwarted by Hak. [/Spoiler]

(Source: Akatsuki no Yona Wiki)

[Spoiler] Later on, under Yona's influence, he started charity work for the most unfortunate in the Fire Tribe. [/Spoiler]

(Source: Akatsuki no Yona manga, Fire Tribe arc)