Stellar Shield

Megastructure the size of a Dyson Sphere (and with a similarly massive energy requirement) capable of protecting the star system it is built in from Nicoll-Dyson Beams. Extremely expensive to build and maintain, so they are only used in very scarce cases. Paragon has one, for example. As the Cypher Hyperquasar Annihilator could not hit the Hyperquasar under Paragon, it prevented the hyperweapon from destroying the Odyros galaxy in its entirety.
All intergalactic factions can construct Stellar Shields.
Stellar Shields will not protect a system from conventional weapons and direct enemy assault however, as those objects are small enough to be 'filtered' through the shield bubble. Anything large enough to collide with the shield is absorbed by the shield, including all types of superweapons. This protection can make Stellar Shields very valuable, and these systems may be very effectively defended and resemble an extremely potent fortress. Deep space weapon platforms also often cannot strike within the radius of a stellar shield. Thes sorts of systems are used for very valuable planets and megastructures to the point where there are only a few thousand within the territories of many major faction territories. The Dyson spheres they are built on can vary depending on faction, but Stellar Shields vary much less, possibly due to having more simple requirements.