The Fist of Kane is a unique building and so it needs one clear plot spacing from other unique buildings.
It automatically supports all alerted friendly bases within range (12 fields) with an artillery barrage in their defense area against incoming attacks.
Additionally, the artillery support can be manually calibrated on one player base (default: own base) within 8 fields to defend that base without being alerted. Artillery support requires weapon calibration which requires 120 seconds plus an additional 40 seconds per field. Only one support building of this type in can be constructed per base.
Damages (for lower levels, damages evolution between level 1 and 65 structures):
Same level as enemy: 3% vs Infantry, 7% vs Vehicles, 0% vs Aircrafts.
1 level below enemy: 1.5~3.0% vs Infantry, 3.5~6.9% vs Vehicles, 0% vs Aircrafts.
2 levels below enemy: 1.0~2.9% vs Infantry, 2.3~6.8% vs Vehicles, 0% vs Aircrafts.