Overlord: Journey of the Creator Goddess Tiamat

A girl who had once been one of Squirrel's gaming friends quit the game for certain reasons. But on the day the servers shut down, she unexpectedly transmigrated with Ainz to the same world.

She, too, became a max-level game character, but this was a unique character she had created herself, which left her with very mixed feelings...

(The Nazarick faction officially appears from Volume 2 onward.

The protagonist's template is from Fate: the beautiful, powerful, and fertile creator goddess Tiamat.)