Japanese Strategic Self Defense Force
The Japanese Strategic Self Defense Force (JSSDF) is a military organization, the main branch of the Japanese military under the direct command of the Japanese Ministry of Defense. It has a background role in the Evangelion TV series, serving in a military support capacity for Nerv. The JSSDF serves as a primary antagonist in ''End of Evangelion''.
The JSSDF was formed in 2003 in response to the outbreak of war between China and Vietnam over the Nansha Islands as a result of post-Second Impact tensions, which prompted the reorganization of Japan's military. As a result of this new political climate, Article 9 of the Japanese constitution (which forbid Japan from maintaining an offensive military force after World War II) was apparently abolished.
The JSSDF arsenal includes N² Mines.
However, in The End of Evangelion, Seele (through the UN) orders the JSSDF to invade Tokyo-3 in a massive leave-no-survivors assault. The JSSDF easily turns on its former allies, mercilessly advancing through Nerv HQ and unconditionally terminating any personnel they encounter.
The "JSSDF" is composed of both land and air units, and presumably naval forces. There are sub-branches of the Strategic Self Defense Force which focus on each military subdivision, for example the "Japanese Air Self Defense Force" (JASDF) is the sub-branch of the JSSDF which is composed entirely of air units (though the JSSDF proper does field its own VTOL airships, etc.)