User blog comment:Raybat/ArchAngels/@comment-5619706-20141108015651

Known canon facts.

i. Castiel is a Seraph (more powerful than a regular angel).

ii. Castiel was also boosted with 50, 000 souls at the time.

iii. Castiel also had all of Heaven's weapons under his belt.

iv. Despite these, Castiel was still weaker than Eve.

v. Eve called the Purgatory souls her "supply".

vi. Said "supply" allowed Castiel (who, remember, is weaker than Eve) to completely obliterate an archangel.

I'll let you decide what happens next.