Based on Jin's likes and several comics, it is heavily implied that he has a crush on Amy. Although if the two are supposedly in the same guild, it isn't known how the two became separated.
Jin was mentored by Victor and the real Asin Tairin and was considered to be Asin's favorite student before Victor went rogue. After Victor descended to darkness and laid siege on the Silver Knights, Asin forced his student to flee while he held off their enemies, but after the ensuring battle, both thought the other had been killed and mourned their loss. After the two became separated, a boy rescued and nursed Asin back to health, and in return Asin trained that boy and told stories of Jin, prompting the boy to declare Jin as his rival and motivating him to become stronger. Sometime after, the two were attacked, but the wounds Asin sustained this time proved to be fatal and he died a few weeks later. The boy mourned Asin and with determination to become strong, he wore his mentor's name in his honor and sought to find Jin. Sometime after Jin defeated Victor and became the Rama, "Asin" eventually encountered his rival, who informs him of the death of the real Asin and then declares he will surpass Jin. Jin then mentors "Asin", who uses both his master's and Jin's training and knowledge to become more powerful.
According to a translation, Jin is referred as the "Red Lion", whose strength and fury are the source of his power.