Actually, a theme in Yu Yu Hakusho that doesn’t get brought up a lot is that Yusuke is kind of looking for a father figure during many points in the series. He’s awful with authority, especially male authority, due to the dehumanizing comments made by his teachers, but he does look up to a lot of older males despite that.
First there’s Takenaka. Takenaka was the first person to believe Yusuke was more than a waste of space, and Yusuke’s never too rude when talking back at him. However, there’s also the aspect of their interactions that it’s Takenaka’s job to encourage and look after Yusuke, so Yusuke would hate to burden him and couldn’t really rely on him as a support because of that. In addition to that, the two were from completely different worlds, as Takenaka is an educator and Yusuke hates school. Takenaka is well-intentioned, but he doesn’t understand Yusuke.
The second paternal figure seen in the show was Toguro. In this case, Toguro very much lives in Yusuke’s world, and Yusuke himself admits that he could have at one point seen himself growing up to be like Toguro. However, Toguro is not a good person. He’s not a role model to be emulated and he’s certainly not someone Yusuke could rely on, regardless of how the man tried to give Yusuke advice on how to reach his full potential as a warrior. In another world that might not have been the case, as even Genkai herself muses, but the theme with Toguro is very much that he gave up on living his life long ago.
While Yusuke doesn’t connect with him on any level, Sensui’s appearance in the show further showcases Yusuke’s disappointment with who Toguro ended up being. Sensui is another example of the “road not taken” in Yusuke’s selection of life choices but, after clashing with Toguro, Yusuke has grown comfortable with himself and his choices, which is why Yusuke doesn’t even listen to Sensui’s attempts to sway him. However, presented in Sensui is another danger is Yusuke’s path that doesn’t get acknowledged; the self-reliant warrior who didn’t make it. Sensui is a prime example of a young man who didn’t rely on anyone and ended up becoming twisted because of that lack of trust.
Regardless of his victories, after his transformation into a demon, Yusuke feels uncertain about his place in the world once more, this time not even feeling comfortable in his own skin. Raizen was the only one Yusuke could turn to, the only older demon who reached out to Yusuke with understanding of what he was now. However, Raizen was distant with Yusuke until his final moments, when he finally opened up, and functioned more as a goal to reach for Yusuke than a pillar of support. Raizen was too focused on his goals to really give the people in his life attention.
Hokushin is Raizen’s primary enforcer. Because of this, Yusuke first meets him rather than Raizen and he functions as the middleman between Raizen and Yusuke. Despite this connection, Hokushin is more similar to Genkai than Raizen. Hokushin is Yusuke’s primary mentor during the last arc, guiding him along and knocking him around until he surpasses Hokushin in strength. After that, he remains as Yusuke’s support and confidant, helping him make his own decisions even when he doesn’t agree with them. To him, Yusuke reaching his full potential is the most important goal to focus on. Out of all of Yusuke’s paternal figures, Hokushin is the only one who never lets him down and understands him the best.
What I’m saying is that, while it took him a while, Yusuke did find a father figure on his journey.
It was the man who was more supportive and proud of him than anyone’s ever been.
tldr; Hokushin is Yusuke’s dad and anyone who disagrees can meet me in the pit.
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