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Major ( Stars Former Head-Captain)
Volume 7, Chapter 10 (Mentioned)
William Sirius (ウィリアム・シリウス) is the former Head-Captain of the USNA's Magician Unit " Stars".
William Sirius is the individual who developed
The most elite of the USNA Military's Magician Unit "Stars", the Head-Captain is code-named "Sirius" is the magician who possesses the strongest magical power.
It's known as a rumor that those bestowed with the title of "Sirius" are front-line fighters. 
William Sirius died in battle during "
The Arctic Hidden War" with the New Soviet Union in 2090. His death was caused by  Igor Andreivitch Bezobrazzoff and his Strategic-Class Magic Tuman Bomba.
Volume 7, Chapter 10
Volume 11, Chapter 13
Volume 9, Chapter 3
Beautiful Girl Magic Guardian Plasma Lina ↑
Volume 23, Chapter 5