Valkyria no Kikou

is a Japanese light novel series written by Rin Yuuki, with illustrations by Kazuo Miyamura. The series began publication on April 10, 2002 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
near future. Mankind and its civilization were hit hard by the invasion of an unknown giant creature called GO (Giant Organic). The UN forces will develop the anti-GO annihilation weapon "Valkyrie" to overcome the situation. However, the entity of "Valkyrie", nicknamed the humanoid all-purpose tank, was a pretty, neat, and incredibly huge beautiful girl ... The heroine pearl, which is 10 times taller, heavier, and bust, becomes "Valkyrie" and protects the world!