The Mech is called the Avid, and it becomes incredibly powerful.
They give it a battleship in its sub space that it can fuse with later. It can easily destroy whole fleets on its own without the ship equipped.
Later on Liam gets a Machine Heart, it tries to use it on Amagi but it doesn't work. So he uses it on Avid. Giving it a self regeneration ability and a mind of its own.