Ruthlessness is a passive ability that can be researched for the Destra Crusader, it requires seven Temples of Hostility and you must have already researched Crusader Design to use it. Its in-game description is "Grants the Ruthlessness ability to Destra Crusaders, allowing them to deal damage over time to nearby enemies." The ability does not stack. Although it can allow you to do 1.5 DPS to all enemy ships in the area, this is barely enough to overcome even passive shield regeneration.
While usually ignored this upgrade is good as it will help a small amount against the regeneration effects of the enemy fleet. This ability goes into a more offensive-support aura then anything else. And it only requires one Destra to channel it. However, a handful of Destras benefits the fleet very well.
Damage per Second
|1||25||3500||Enemy Frigates/Capital Ships/Starbases/Titans/Structures/Corvettes|