Swarmtower
From Project Nomads Unofficial Wiki
The Swarmtower is a firemissile type guntower. It is the only guntower capable of firing seeking missiles.
Obtaining
In chapter 3, part 2 "Fighting a Losing Battle", a friendly NPC Swarmtower can be controlled, but not obtained.
In chapter 3, part 4 "The Refuge", picking up a Swarmtower artifact is mandatory for the completion of the objectives. It will be usable at chapter 3, part 4 "Mare Lacrimae"