Saku Tatsuhiko

Saku Tatsuhiko (佐久 辰彦) is the leader of BLOCK

He is a big man who is constantly described as "bear like". He displays a serious "no nonsense" personality and leads BLOCK's revolt through a series of complicated plans and strategies meant to fool Academy City's higher-ups. His plans included large diversion tactics involving SCHOOL, GROUP and using 5000 hired mercenaries. He seems to be fond of ruthless tactics, a fact that eventually ended up with him being taken out by Teshio Megumi, another member of BLOCK.

The goal of his revolt is being able to escape from the Academy City's world, where everything is under Aleister's control. The first setback to his plan arrived when Etzali used an indirect method to alert Academy City's defense system and the unmanned helicopters known as six wings, and the 5000 mercenaries he hired where almost entirely wiped out. The second setback to his plans was getting involved with GROUP when they tried to squeeze out Move Point's identity, to the point where Teshio grew tired of his methods and knocked him out with a fist in the face.

He wasn't killed, he was just knocked unconscious. Considering the situation in which he was taken out, it is quite likely that he was apprehended afterwards. He seemed to have a close relationship with Teshio Megumi