User blog comment:Nekokokokoko/Slane Theocracy's awareness of Ainz/@comment-26501532-20150920141320

Yes, the fake knights that returned alerted them about Ainz Ooal Gown but Slane thought it was someone else who wiped out Sunlight Scripture, that was explained in vol 3 that they thought it was something else that wiped out Sunlight Scripture that countered their spying magic, thus they sent Black Scripture.