I reread s1 ch 30 and 31 and I saw that Daiki was married to Ueyama Miu, so s2 ch30 would mean that Taichi and Miu are the actual siblings. This new ch would confirm imo, since Taichi didn’t like Daiki being the oyabun in the beginning. But in ch30 Sho said Daiki was similar to Takeru (the dad), so I think that Daiki grew up with Miu and Taichi, then ended up married and having Toma with Miu. There was some stuff Sho said about Daiki being Takeru's son or something, but maybe Daiki was adopted by the clan because his family was their friends. Daiki is ethically Korean not Japanese but his family has lived in Japan for a while so his family might be members of the clan. here's my new family tree with reoccurring side characters: https://mangatoto.net/aok/xfs/attachs/62a3329fb57f9b4f307097bfe97f46890170787b_1636_1174_220013.jpeg
I reread s1 ch 30 and 31 and I saw that Daiki was married to Ueyama Miu, so s2 ch30 would mean that Taichi and Miu are the actual siblings. This new ch would confirm imo, since Taichi didn’t like Daiki being the oyabun in the beginning. But in ch30 Sho said Daiki was similar to Takeru (the dad), so I think that Daiki grew up with Miu and Taichi, then ended up married and having Toma with Miu.
There was some stuff Sho said about Daiki being Takeru's son or something, but maybe Daiki was adopted by the clan because his family was their friends. Daiki is ethically Korean not Japanese but his family has lived in Japan for a while so his family might be members of the clan.
here's my new family tree with reoccurring side characters:
https://mangatoto.net/aok/xfs/attachs/62a3329fb57f9b4f307097bfe97f46890170787b_1636_1174_220013.jpeg