Alright, so I just finished season 4 of the dragon prince, and I know everyone is wondering why the hell Viren was able to adopt Terry (and Sir Sparklepuff) yet not able to speak to his own son. I was frustrated as well, as I've really been enjoying his characterization this season as seeming apprehensive and somewhat scared of what Claudia has been doing, and I wondered if this would lead to regret for his past actions.
I don't think that Viren will get a full redemption arc, but I do think that he probably didn't speak to Soren because he felt shame and confusion for how he treated him, and it was easier to just ignore his presence than acknowledge what he put his son through. With Claudia so intent on restoring Viren's life, it must serve as some hope that he was doing the right thing, however as he sees Claudia's descent into darkness, he becomes less and less sure of his past actions and feels more guilt that he can't bring himself to face. Seeing Soren is the personification of all that doubt, and he's just not...strong enough to face it yet.
Terry has not had any history with Viren; Terry serves as an exploration as the father Viren could have been to Soren, had he not been obsessed with power. Terry is silly and goofy and even irritating to Viren, and yet even with that, Viren is able to show some form of affection, however small.
I have a feeling Viren's story is going towards a Shadoweaver-type end, where no one really forgives him because his actions are irredeemable, and he's not a good person, but he is capable of love and care for his friends and family. I think come next season, we will get that conversation between him and Soren. I don't think that it will be wrapped up nicely in a bow, but I think Viren's complex feelings toward his son that he's developed will be vocalized and will lead to a turn.
On that note, I'm reminded of Soren's speech about his father being evil last season and his eagerness and pride in being one of the "good guys" this season. I love Soren, and he's grown a lot in this show, and I think he still has room for even more growth. He was able to escape his manipulative father (and please don't confuse my desire for a Viren-Soren talk for a need for Soren to forgive his father), and his perspective of the world changed drastically. But it's clear that he currently sees things in black and white, good and evil. He wants to pull Claudia to "the good side", his father is "evil". And in the time he captured Claudia, he only told her not to do something because it was wrong and evil instead of trying to understand why she would do something he sees as evil.
Anyway, this season was a lot of interesting setups, and I'm very curious to see where the writers take it.