Malgal and YeoJin are separate.

 Considering the history of thousands of years in our northern ancient lands, contrary to what is commonly believed, the suspicion that malgal and aftershocks are originally different is well-grounded and believed. Goguryeo was originally a cultural person. They were not just hunter-gatherers, nor were they horsemen in the meadow. It is highly characterized by urban-state settlers who are good at hunting, excellent in horseback riding, and have been farming and livestock. Later, Goguryeo people merged and ruled Malgal, but it seems that Malgal was not a Buyeo-gye, but a less civilized indigenous people of the Samhan system (especially Jinhan). Anyway, I think they were formed and more civilized by the Goguryeo people who flowed in during the reign of Goguryeo. Malgal, who has been culturally and traditionally Goguryeo, will later share the leading role in the founding of Balhae. Looking at the remains of Balhae, there is nothing that is not Goguryeo, regardless of whether it is royal, temple, or residence site. However, looking at the aftershocks of this era, they maintained an uncivilized lifestyle at the time of Balhae, after the fall, or at least until the founding of the Geum Empire of Aguta, and were far different from Balhaeans. After Balhae collapsed, approximately 100,000 people led by Prince Dae Kwang-hyun came to Goryeo. Of course, Balhae Yumin's journey to Goryeo continued even after that. And there is a record that another large group entered the aftershock. If Malgal is an aftershock, isn't it absurd to say that Malgal ran away to aftershock, a Goguryeo and Balhaean, aftershock flowed into aftershock, and thus Malgal seems to have become recognized as an aftershock soon. Of course, the Malgal here is a group including Goguryeo people in Seongeup. When reading Songmakgimun or Samjobuk Maengshoe written by the Chinese during the reign of Hwabuk, the people themselves say they are descendants of King Jumong, and Yeo Jin-in, in the opinion of the Chinese author, is a descendant of the late (former) Ryeo Jumong. In other words, it is presumed that Yeo Jin-in, who came over the Jangseong along with the Wanan clan of Silla, was a Goguryeo-style horse man who had been ruled by the majority of its components and was a Goguryeo-style horse man who had long been the people of the kingdom. They were pedigree and cultural Goguryeo people who held ancestral rites for King Jumong and King Gwanggaetotae every year. Of course, even for 120 years when the Geum Dynasty ruled China, the aftershocks of an uncivilized lifestyle in the Baeksan Heuksu basin have been leisurely protecting the land.