There are seven goddesses, and four of them have compass directions, and the other three have intermediate directions. Facing one or sending Path to fly in such a direction while she casts boosts a call to a goddess. (She's still not sure what the other motions do, if anything; they get erratic results. But she's sure about facing, and about Path's flight.) The southeast is unmarked, and facing or sending Path in that direction will amplify a spell that falls under no particular goddess's purview.
As soon as she has this figured out, she slots it into her elaborate draft of a one-target immortality spell.
She goes looking for Kas when she's rewritten the final verse and placed the final margin note.
"Hi, sweetie! What's up?"
"I have," she says, brandishing her notebook, "a spell draft."
"...Come here and hug me," he demands, setting down the alethiometer and holding out his arms.
"You could ask the alethiometer if it'll work, so I don't spend all afternoon casting this ridiculously complicated thing and then watch my runes not disappear," she suggests, snuggling up.
Will her immortality spell work right?
Questioner—lifespan—becoming—unbounded/
"Well, that was weirdly specific," he says. "It'll work on me, apparently."
Spell—object/target—difference—spell—
"...Who it's cast on makes a difference to how you have to cast it," he translates.
"Oof. That's going to put a damper on the scaling-up project. ...Ask it if scaling up is even doable?" she prompts, tucking her head under Kas's chin.
"It says 'eventually'. As in, 'can she cast it on everyone?' 'Eventually.'"
"Okay. That definitely means I can scale it up at least some, since people are born much faster than I can write all these runes, let alone kill a deer and recite seven segments of several stanzas each. But for now - I have this one worked out, it'll work on you, wanna watch me paint the runes that'll help make you able to live forever with me?" She grins winningly.
The basic design is a compass rose, with each point made of runes in a different substance and then sprinkled with a different cocktail of herbs. "You're both going to stand in the middle," says Isabella. "But not the exact middle. Petaal should go and be witch-shaped at the east point and you should be at the southwest point."
(Metis has a harness set up specifically for holding large sacrifice animals that can't be clenched in one hand after their docility fades. Isabella goes and makes sure it's secure.)
Petaal fetches silks, bewitches, and gets dressed. Then she and Kas take their appointed places.
The poem is long, and despite her assertion about having it memorized, she consults her notes during the recitation. Every compass point apart from the one Kas stands at is addressed by goddess, and by their moon phase or sun or starlight or Evisa Iannakara's oddball light-element of bioluminescence, and other relevant portfolio items. She's entreating them each to lay their hands (metaphorically) on Kas and his daemon and offer them the agelessness that witches enjoy.
At the last part, when she entreats Kas Petaal the patron of sacrificial magic, she sends Path on his last flight out along the compass point and she herself dives to take the life of the deer. It breathes its last as she utters the final word: "always".
Then he flings himself at Isabella and kisses her.
He manages to knock her off her cloud-pine, but she doesn't mind, she's all over that.
"Welcome to being immortal," gasps Amariah between kisses. "How's it feel?"
"Like starlight," sighs Petaal, pressing her face against the back of Amariah's neck. "We love you so much."
"We love you too," says Path. (Isabella's mouth is busy again.)