Hiroshi and Haruka both have brother complexes towards each other. Hiroshi also loves his brother's white hair.
Hiroshi also has this with Ogino. It's the main reason Yuuta wants Ogino dead.
Rather this is a surrogate father/son relationship, that's why Kei referred to Ogino and Yuuta argueing like in-laws.
Kei hugs Yataro when he thinks he's a bodypillow in the Highschool AU episode.
When Haruka's captured Kei, as he reveals his mind-reading powers to him, Haruka places his hand on Kei's chest, and then proceeds to continually rub it as he monologues. This was likely meant for comedic effect, but that is not what it came off as.
Tear Jerker: "I toughed it out again and again, and before I knew it, I was only holding myself up." Sniff.
Soumei being forced to kill the young werewolf girl who'd tasted blood.
The memory of his partner is what stops Soumei from shooting Hiroshi. Afterwards, he admits he's the only one who hasn't gotten past what happened thirty years ago. It's clear Joji's death never stopped hurting him.
The Woobie: Despite being a lecherous pervert who seems a bit too fond of trolling, Soumei really is one. And taking into consideration Haruka and Hiroshi's pasts, they can be considered this too. It's just not that obvious yet, what with the... fetish and the bro-complex.