First Light is about an underground society. Great.

Amazon.com says,

"The father of 12-year-old Peter is a glaciologist, his mother, a genetic scientist. Peter is thrilled when his father decides to take the family on his latest excursion to Greenland to study the effects of global warming. Fourteen-year-old Thea lives in a secret society called Gracehope under the Greenland ice. After finding a map that leads her to the surface, she becomes obsessed with seeing the sun and bringing her people back above ground. Peter and Thea accidentally meet on the surface and discover, through a secret kept by Peter's mother, that their destinies are unexpectedly joined."

Amazon says,

"About three things I was absolutely certain. First, Edwart was most likely my soul mate, maybe. Second, there was a vampire part of him–which I assumed was wildly out of his control–that wanted me dead. And third, I unconditionally, irrevocably, impenetrably, heterogeneously, gynecologically, and disreputably wished he had kissed me.

And thus Belle Goose falls in love with the mysterious and sparkly Edwart Mullen in the Harvard Lampoon’s hilarious send-up of Twilight.

Pale and klutzy, Belle arrives in Switchblade, Oregon looking for adventure, or at least an undead classmate. She soon discovers Edwart, a super-hot computer nerd with zero interest in girls. After witnessing a number of strange events–Edwart leaves his tater tots untouched at lunch! Edwart saves her from a flying snowball!–Belle has a dramatic revelation: Edwart is a vampire. But how can she convince Edwart to bite her and transform her into his eternal bride, especially when he seems to find girls so repulsive?

Complete with romance, danger, insufficient parental guardianship, creepy stalker-like behavior, and a vampire prom, Nightlight is the uproarious tale of a vampire-obsessed girl, looking for love in all the wrong places"

Amazon.com says,

"In this fifth book in the Magykal series, Septimus ends up on a captivatingly beautiful island, one of seven set in a sparkling sea. He's stranded there with his badly injured dragon, Spit Fyre, along with Jenna and Beetle. There are some strange things about the island, including a Magykal girl named Syrah, a cat-shaped lighthouse that has lost its Light, and an eerie presence that sings to Septimus—can he escape the persistent call?
Trouble is also brewing for Lucy and Wolf Boy, who have become entangled with some nefarious sailors at sea, and for Milo Banda, Jenna's father, who is harboring a mysterious treasure chest in his ship's hold.
Charismatic storyteller Angie Sage continues Septimus Heap's Magykal journey with more laugh-out-loud adventures, more enchanting charms and spells, and an ever-deepening understanding of the interior life of a young hero."