Tentang
Ocupation: Hunter
Rank: D-Rank
Class: Tanker
Guild:
Ah-jin Guild (Vice Guild Master)
Yoo Jin-ho is Jin-woo's best friend. Jin-ho is fiercely loyal toward Jin-woo and seems to have a desire to make his own living, which likely stems from his high-society background. A running gag to his character is his odd habit of dressing up in very flamboyant and expensive armor whenever he goes on raids.
Jin-ho met Jin-woo at Hwang Dong-suk's raid party. Later on, he asked Jin-woo's help in order to become the guild master of the future Yoo-jin Guild by completing 19 more raids with him in exchange for a building worth 30 billion won (about $26.8 million USD).
As they went through raid after raid, Jin-ho eventually became Jin-woo's best friend, and the two ultimately developed a brotherly relationship.
By the time their deal had been completed, Jin-woo had already become a S-Rank, and thus, the building that Jin-ho had promised him was of no use to him anymore. As a result, Jin-ho ultimately dropped his aspiration of becoming the guild master of the Yoo-jin Guild and opted to join Jin-woo's guild as its vice guild-master instead.
Jin-ho then went on to accompany Jin-woo in their first few A-Rank dungeon raids and even went with him to Japan for the Shinjuku Raid.
(Source: Solo Leveling Wiki, edited)