frankly:

If we think about how the drugs manifest, the one Bei Hai created gave the soldiers purple veins and they became strong for a while before reverting back to their normal selves…and then a couple of days later they would become “monsters”. The powder General Huo took in the tea in small amounts made him remember the massacre, going crazy (and strong?) over time. The immortality pill that Gu Ghuang Sha took made him remember the massacre, going crazy, and Qing Zhuo mentioned that they guy bled from his orifices (did it make him strong though?). The pill Old Bug took looked to have made him strong but not crazy, based on his eyes when confronting Xue Man. The Luo Shu’s brother was both crazy and strong. But looking back at these people, none of them seemed to have exhibited the purple veins + weird backbones sticking out.

Before he got the last version , he might have had some failures. Luo Shu’s bro must have taken one of these failures. 

 PeachBlossomGoddess:

Yes there are other terms but those are the most commonly used. It doesn't really matter whether Beikun or Beiming is the older one. In any case I no longer think Kongyun is Beiming's brother. MAJOR SPOILER -  It is more likely that it is coroner Feng, the little white dragon.

Right. Bei Hai did tell Zhong Yun to go to Poison Valley to drop off the pill. If that’s the case, his name would not have been recorded in the orphan list, perhaps because he’s not in the capital. And Bei Hai did say that if the Poison Valley Master can’t figure out the antidote, then the future generation would. So one kid went with Zhong Yun to help quell the blood feud between Qi and Haiya (Zhong Yun raised him especially for this) and the other kid went to poison valley to help develop the antidote (Poison Valley Master raised Qing Zhuo especially for this). Both brothers working to resolve the Haiya massacre from different angles. Also Bei Hai said he respected Zhong Yun as they solved cases together (which one of his sons, Bei Ming is doing) and he also admired the Poison Valley Master for his exceptional talent for concocting poisons/antidotes (which the other son, Qing Zhuo is doing). Dude…the writing is great if this is the case…and even if it isn’t, the writing is still great because it’s been so fun and interesting looking at all the different clues and trying to piece things together along w/ the team.

 miss:

The moment they learn the mark  , camera focuses on Bei Ming first then showes Tong Shuang’s shocking face. Even after they try to get out of the cave , Tong Shuang  saves Bei Ming and disappears somehow. That is the part I think that TS is bro. 

However, Xiao Bai Long fits in the story better than TS. He is from Poison Valley like Bei Hai. His master is Bei Hai’s big brother. ZYC gives the baby to his uncle to raise him. He even has a nickname Xiao which is her mother’s name like Bei Ming has .

Yes, I agree…I think it must be Xiao Bai Long/Qing Zhuo. Love that they both have Xiao names…that would definitely be a clue to their relationship….awwwwwww!!!

 frankly:
his name would not have been recorded in the orphan list, perhaps because he’s not in the capital

Yes I think Zhong deliberately omitted reporting Beikun as a Haiya orphan bc no one needs to know about him. But he had to report Beiming bc he was adopting him himself. The rest of what you posted is more or less what I also think happened.

 PeachBlossomGoddess:

Yes I think Zhong deliberately omitted reporting Beikun as a Haiya orphan bc no one needs to know about him. But he had to report Beiming bc he was adopting him himself. The rest of what you posted is more or less what I also think happened.

Right. Zhong would want to protect Bei Kun because his work would be important in the future and can’t be compromised, whereas he can personally protect Bei Ming.

 frankly:
But Tong Shuang knows that Bei Hai had burned an incense stick on the right shoulder of his kids…

Wow.  I missed watching that!  I've got to stop watching these when I'm still half asleep.  lol

 frankly:
Right. Bei Hai did tell Zhong Yun to go to Poison Valley to drop off the pill. If that’s the case, his name would not have been recorded in the orphan list, perhaps because he’s not in the capital.

Ahhh, that makes sense.  Good catch!

 miss:
He even has a nickname Xiao which is her mother’s name like Bei Ming has .

They sound the same, but I don't know if those are the same, however, as I haven't seen the character.  For the corner, Xiao means Little.  As a surname, like Xiao Bei Ming, it might be a different character and meaning.  That said, word play with the way characters sound seems to be a big think in China, so it would be the same intent -- a 'hidden' clue in plain sight.

 miss:
Old Bug did sth then. Nobody comes to my mind except him.

Well, we got the answer today in episode 31.  I can't believe I was inadvertently right with my idiom.  LOL!  It was in the water!

Though, I think Frankly brings up a good point about the various different effects being a result of the pills being refined / created slightly differently trying to fix the side effects.