First, we have Sousuke Sensei who raise Taeko like his daughter and married her. Taeko also end up one as well after The Reveal.
Nicchi, who came across comic relief guy straight to Jerk Ass when he helping Nozomi kidnap Kanau from Kouta and for being overall irresponsible jerk for everybody feeling. It doesn't help that he is also a Karma Houdini when everyone don't call on him from the above action
There's also Nozomi who kidnaps Kanau and her brother from their fathers without considering their feeling into account. Worst yet, she never loved Kouta from the beginning and used him to make Nicchi jealous(which backfired gloriously). She also did something similar to her soon-to-be husband as well. It doesn't help that she takes Kanau and tells the truth to Kouta in jerkiest way possible.
The amount of sibling rivalry and parental favoritism that goes on without even a mention sometimes weirds out readers from different cultures.
Also, people from more individualistic cultures like America might have a hard time understanding why Kouta should have to give up on his crush just so Kanau can have her estranged parents back together. Of course, the Wham Episode makes the whole thing moot anyway.
The aforementioned openly pedophilic man used as a comic relief is something you'd never get away with in most of the western world.
The Woobie: The Nagato Family. they are The Faceless who just want to be noticed by the rest of Higansou. Kind of hard not to feel sorry for Them.