...all of that summarised - perhaps as a 'basic guide' for all the new-comers into related affairs - and by your very own:

A New State Is Emerging in Yemen
A new country is beginning to form in the chaos and confusion of Yemen’s civil war. A coup in Aden in late January 2018 has hastened the process.

The new Yemen has its roots in the period 1990 to 1994, when the Saudi-supported North Yemen and the Cuban/Soviet-supported South were forcibly united. The united Yemen was dominated by a clique surrounding North Yemen president Abdullah Saleh.

Although he eventually appointed a southerner – Soviet-trained Maj. Gen. Abdrabbuh Mansur Hadi as his vice president, Saleh ruled the country like a family enterprise. He appointed his son, nephews and other members of his family and tribe to all important positions of the military and the state.

All the power, and most of development, were concentrated in Sana’a, and the Saleh clique had the final word in every single state affair.

Saleh and his clique tended to disparage the southerners as “Eritreans” and “Indians,” because Aden was predominantly populated by people who came the region as laborers during the British colonial period.

Saleh and his clique likewise discriminated against many northerners, describing those of Zaidi origin as “backward.”
...