User blog comment:Piyush Banerjee/Shin DxD 2 discussion/@comment-2208155-20181221114645/@comment-2208155-20181221200906

... I don´t know how explain this but.. One evil god and his 2 brothers? will invade this world in 3 decades, Issei needs be more powerful than Ophis(this God is stronger than Ophis) and GR to defeat them..

These mechanical lifeforms were part of his subordinates, I think..