I'm a Behemoth, an S-Ranked Monster, but Mistaken for a Cat, I Live as an Elf Girl's Pet, Vol. 4 (manga) - Barri Shrager - Bog

Is the cat finally out of the bag? Finally healed from her injuries and clad in an alluring new outfit, Aria is ready to go back to adventuring with Tama and Vulcan! However, their expedition is abruptly cut short when they run into an unarmed and disheveled girl in the depths of the labyrinth…who says she wants to have Tama’s child?! The party agrees to take her in out of concern for her well-being, but Tama can’t shake the sense that he knows her from somewhere—and what she turns out to know about him could expose his secret once and for all…