A remote piloted heavy weapon with a heavy fusion device as a warhead.
The fuse is only armed once the firing ship is out of the weapons blast radius, moving the small antimatter detonation charge into the missile centre, ready to initiate the fusion reaction with a small high energy matter / antimatter explosion. The warhead fusing allows it to be detonated by proximity to an enemy or on command via the remote link.
Remote missiles have a large blast radius.