Most powerful/effective weapon.

[BayGateScape]

Planet Killer Ships from B5.

[thekillman]

actually the Ori and Ancients are equally large groups. the Ori wanted worshippers to outbalance the ancients. seeing their arrogance and selfishness, a straight-out war would've caused too many losses. it's canon that a direct battle would be bloody. since earth would be the last nail in the Collective's coffin, the ori galaxy had a few billion worshippers at most.

[lordofseas]

actually the Ori and Ancients are equally large groups. the Ori wanted worshippers to outbalance the ancients. seeing their arrogance and selfishness, a straight-out war would've caused too many losses. it's canon that a direct battle would be bloody. since earth would be the last nail in the Collective's coffin, the ori galaxy had a few billion worshippers at most.

Proof is? I'm tempted to believe that the Ancients left the Ori alone until it was too late. Morgan didn't think the Ori were threatening until she realized Merlin was right.

[thekillman]

both sides are equally powerful, the war will be bloody and earth as worshipper would tip the balance in the ori's favour