Ikai Shinki to no Reunion

Ikai Shinki to no Reunion (異界神姫との再契約〈リユニオン) is a light novel series by Kota Nozomi with illustrations by Merontomari.

Plot
A young man named Kurosu Tooi was summoned to another world. He commanded 12 beautiful goddesses to defeat the demon king in order to return to his world. After a year, he returned back to the other world, but ten years had already passed there.

"Long time no see, Tooi Oniichan."

"Did you fall in love with my breast?"

His other world comrades have aged. However, the 12 Goddesses (Nebulosa) Tooi released are on a rampage in every parts of the continent.

"Cry in joy, Tooi Cross. The enemies this time are the women you loved."

His strongest servants are now his strongest enemies. It's time to save his scattered comrades; in his second coming to the other world, he has to fight, talk and make them fall for him! Let the curtain unfold, for this an Reunion fantasy of obtaining the strongest Goddesses (Heroines)!