Elven Heritage.

Perhaps it was your birth mother's heritage showing itself in you, but you fancied a challenge. Oh, certainly the convent would provide one, but what advantages did THEY bring to your brood, hum? Chastity? Virginity? You cared not one whit for these things. No, you are a spider, and the future of spider kind at that, and what you desire is STRONG brood mothers for your offspring, ones that will impart greater power to your children.

For that, clear as day, you want the elf.

You leave the steeple and cross the grounds swiftly and silently, returning to the half elf quarter and the bedroom where you left the woman you would make your first brood mother, it is summer and the window is still open for the breeze it will provide.

There she lies, skin practically glowing in the moonlight and pert B-cup breasts tenting the fabric of her shift, she doesn't even have the covers pulled over her in the heat of the night, just a thin shift of silk which leaves next to nothing to the imagination, you can even tell that her pussy is 'au-natural' though for elves that is restricted to a small patch on the 'mons' itself, not the dense labia enfolding thicket that human and half-human women have if they don't shave, and you begin to salivate over your prize.

It's a tight fit into the room, a hard wiggle and scuttle which rips out a few of your hairs, but you manage to do it without making much noise and you climb across the ceiling to be above the bed.

With the patience for which your race is known you lower yourself on a silk strand, coming down gently crouched with eight legs surrounding your victim, and...

You realize she is not asleep, she's only pretending to lure you in!