Degwin Sodo Zabi
Degwin was Zeon’s chief of staff and claimed that on his deathbed, Zeon, with his dying words, declared Degwin his successor. Given this much, general consensus tends to automatically connect Degwin Zabi with the sudden death of Zeon Deikun, but nothing concrete has ever been uncovered.
Degwin initiated a purge of Deikun loyalists and declared Side 3 colony the Principality of Zeon and himself as Archduke. He initiated a war with the Earth Federation and set his children up in high ranking positions.