Excalibur is an experimental Photon Sword created by the Australian IS Institute, lead by Samuel Hayden. As of right now, the sword is in a specialized containment vault called Avalon at a undisclosed location on island.
Excalibur is an Photon Sword which has the capabilities of slicing almost anything through by the barriers used by the IS, but can greatly damage them either way. It was made in 2020 just a few years after the introduction of the IS. In other words, as soon the Australians got their IS Cores, they were already at the 4th-Generation, and was even already researching for the 5th-Gen.
The sword was then start to finalize for more practical experimental usage, and so the 5th-Generation IS, Albion Cove was the first IS to use it. However, due to the power needed to actually use the photon sword, it backfired, and caused the IS to shut down. This placed budget issues on the research. However, Samuel Hayden was able to get things back on, and propose the research of the 6th-generation. Despite almost all other countries just started doing 3rd-gens, Samuel still done it, and created the 6th-Generation IS, Cuidightheach.
Later, the Photon Sword wad given to the IS, and to the pilot for use, and it worked brilliantly. As Samuel secretly "upgraded" the IS Core, allowing it exert even more power, and with the 6th-Gen, can regulate power, and control it, without wasting the energy.
However, due to the Alaska Treaty, Samuel was forced to seal all deadly experimental weaponry into Avalon in hoped no enemy could use it.