Katara hadn't known Senna, not personally. Sokka had mentioned her once or twice, as he and Tonraq got on well, but she was just another woman of the Southern Water Tribe to Katara. Other than the fleeting thought that she hoped for more water benders in her home, Katara didn't spare her a thought.
It wasn't that she was particularly busy-at sixty-eight, her life was beginning to wind down. She and Aang spent a lot of their time walking around Republic City, hand in hand, or giving lessons to the Air Acolytes. And of course, when the occasion called for it, Aang would launch into an embellished recount of one of their adventures from when they were young.
It wasn't that she never spared a thought to her childhood home, was just that Bumi had just been promoted within the United Forces, Kya had recently decided a trip around the world was in order, and Tenzin had broken up with Lin and had taken up with Pema. Her children occupied a lot of her time, of her thoughts. Nearly as much as her husband. She was content with living in the moment, with taking things as they came.
Until she caught Aang speaking to the White Lotus one afternoon.
"Take care of the next Avatar," he advised them, "make sure he or she knows who they are from a young age. Do not wait. This is a new time we live in, and some of the old traditions must be forgotten if they are to be remembered."
Eager to obey him, she thought, they assured him they would. And then they assured him he would have a long life yet, many more decades with his family.
Of course he would, Katara scoffed. She was one of the best healers in the world; if he so much as got a paper cut, she would heal him. And he would be perfect again.
Still, she couldn't help but confront him.
"I heard you talking to the White Lotus," she begins, not accusatory, but definitely curious.
"It was just a passing thought," he says, quick to reassure her. It does not immediately appease her, and he presses a kiss to the crease in her brow, "and I didn't have anything to write it down with."
She stares at him a while longer and then snuggles into him, exhaling happily. "You'll tell me, won't you? If you ever feel sick? If you ever… You said you can tell, sometimes, that it was another part of being the Avatar. You'll tell me. Right, Aang?"
He exhales, and eventually nods. "I love you, Katara. Please don't worry."
So she didn't.
"Tonraq says the baby is due soon," Sokka comments flippantly, eyes scanning over some new report or another. Katara has stopped asking him about them; if he wants her to know, he will tell her.
"I suppose you don't miss having babies?"
Sokka laughs, but coughs, a bit uncomfortable. "Suki and I both don't miss it." He assures her. "Three was enough."
"It's only their first," Katara laughs. "It's impossible to know how many children they will have."
"Three is a good number," he says again, smiling, "I had three, you had three, Zuko, Toph… It's a tradition, baby sister."
"A tradition for whom?" she demands, raising a brow in challenge.
"People?" Katara prompts, smirking.
"People who… associate… with the… Avatar?"
Katara shakes her head, knowing she's won. "I guess we better go visit them, then."
"Master Katara! Lord Sokka!" An acolyte bursts suddenly into the room, nearly collapsing on the threshold of the door. "Come quickly! It is Master Aang- He- He is not-"
Ice runs through Katara's veins, and then she is sprinting. Her bones have grown tired, her joints achey, and she decides half way through to bend water to carry her to him. To find… whatever's wrong, and to fix it. A warm up, she decides, so she can heal him properly.
"Aang!" Katara shouts, foolishly attempting to reign in her panic. "Aang!" she says again, as though the entire world can hear her heart breaking.
Aang wheezes, attempting to sit up. She forces him back with only a look, summoning water to her hands from the pouch she still-after all this time-carries on her hip. It floods her hands and she lets her her hands hover over his abdomen, glowing.
Healing works with chakras, which aren't too different from blood. Skilled healers can tell when the chakra flow has reduced, and if that means a chakra has closed, or if there simply isn't very much chakra at all. But this… she's never felt this before.
"It's like…" she gasps in a pained voice, blind to everyone else in the room but him, "it's like your chakra is leaving you…"
Aang smiles and catches one of her glowing hands. "Katara," he manages, "I can feel it."
Katara's lip trembles violently and the tears cascade over her bright eyes. "You can't." She orders, sitting up straighter and glaring. "You can't, Aang, you can't. Don't you dare leave me!"
"I won't," he says softly, "I won't ever leave you."
His temper, so opposite from hers, has always allowed him to remain cool in a crisis. Katara, with any foresight to this, might have hoped hers would remain in check at his death bed. But that is not the case.
"No!" she says again, clutching both his hands fervently and then running her hands over him again. "No, you can't! You're not leaving me, Aang!"
"Okay," he breathes, pressing his nose into her hair when she lays in the bed with him.
"He's lying," breathes Toph, so quietly Katara might have missed it over the too-loud beating of her own heart. Not that she needed Toph to tell her her husband was lying to her. Not that she needed Toph to feel everything it is that makes Aang Aang fading away.
"Toph," gasps Katara, looking up-she doesn't dare move away from him; she fears every breath he takes will be his last- "Toph, you can tell, can't you? You can feel his heartbeat? Don't you think it's strong? Don't you think-"
Toph shakes her head. She does not tremble, but Katara can see that even the renowned, tough-as-nails Toph Beifong is crying.
"Katara," Aang gasps, "tell our children-" he coughs weakly. A smile pulls at his mouth when he is done, and he reaches a hand up to her face. "Tell them I love them. Never forget," Aang continues, with apparent strength were it not for the volume of his ever-fading voice, "never forget how much I love you. That will stay with you, Katara, I promise. For all your days."
"Aang-" Katara's voice breaks painfully from her throat even as she throws herself at him and sobs into his chest, her entire body convulsing. Aang's arms lift around her, and she cries harder.
"Bye, Toph," Aang whispers, "You invented a whole new style of bending, a school, you're police chief, your daughters- they're great. Don't be a stranger, okay?"
"I won't. T-Twinkle toes."
Toph's stutter is not lost on Katara, whose sobbing has escalated to a full-on panic attack.
"You were my best friend," Aang tells her older brother, who's crying quietly in the background. "You always will be. You and Suki, and your children, you're going to do amazing things, Sokka."
Sokka nods, Katara thinks, because he does not trust his voice.
"Sokka, take care of her. Don't let her forget." Aang continues, and Katara sits up because now she can tell. Perhaps it's all her time around an Avatar, but now she can tell his spirit is fading. Can practically see it leaving his body.
"Aang," she gasps, her face contorted and her breathing haphazard. "Aang, don't leave me. Please."
"I won't ever leave you," Aang vows, kissing her softly a last time. "I will always be with you. I'm the Avatar, remember? I won't ever really die."
"Aang," Katara gasps anew, clutching his hands in her own, simply because she does not know how many times she will call him his name to his face.
"Katara," he smiles.
But he can't fool her. She sees them. She sees that he's crying, too. Quietly, in a dignified sort of way, but she sees his tears.
Aang only has a few more breaths, and then he slumps, and his hands go limp in hers. He stops being quite so warm, and he is gone from her.
Katara's sobs alert Tenzin and Pema of their father's death. Their footsteps race into the room.
"We came as quickly as we could-" explains Tenzin, "What is-?"
Tenzin's eyes take in the scene in impressive time, and he crouches beside his sobbing mother. "Dad?" he tries, unsuccessfully blinking the tears from his eyes. "Dad?"
Katara cries harder.
It takes both Sokka and Tenzin to pull her from Aang's body. His robes are stained, soaked with her tears, but it's not enough. Nothing will ever be enough again.
She cries into Sokka's arms, and then Tenzin's. Some hours later, when she is able to stand (her body, she thinks, is the only thing about her that still works), she still has not stopped crying.
"The acolytes said it was likely his time in the iceberg significantly shortened his life span," Tenzin says academically, but gently, his hand on Katara's shoulder.
Piercing guilt threatens to drown her, guilt that she did not find him earlier. Katara, she hears him say we cannot change things that are long past. Please don't feel badly. Her tears renew, and her knees give out.
Zuko stops by, by which time Katara still has not stopped crying. The acolytes keep trying to make her drink water, to make sure she stays hydrated. She forces down what few gulps she can only because she knows Aang would want her to.
Kya and Bumi come home, and Katara clings to them. They are her and Aang, the last piece of her soulmate she has.
And then the news comes, about Senna's and Tonraq's baby. A little baby girl, born the day Aang died. And Katara hates her.
For all Aang's preaching, all his words of wisdom about how hatred only poisons a soul, she hates the baby that took her husband from her. She hates Senna. She hates Tonraq. But she hates Republic City more. She hates the state of her husband, the statue that always embarrassed him, the statue she always told him made his beard look too big. The statue she could turn his ears red with.
Everything here reminds her of him, so she must leave. For a while, she goes with Kya. But adventuring somehow makes her sadder than being in Republic City, so she goes home to the South Pole.
She avoids the baby, and Senna and Tonraq, for as long as she is able. She and Kya help out the village, construct new huts with their water bending, attend to the other children-the ones that did not take her husband from her-and gather food. Katara takes care to leave a room when Tonraq comes in. Senna is home with the baby, so Katara avoids her easily.
Until one day, she cannot.
"Please, Katara, you're the best Healer in the world- Please, look at Korra!"
Korra. It takes every shred of will inside Katara not to scowl.
"We don't know what's wrong with her. She will not stop crying. Is she sick?"
But she knows Senna's look, the worry of a mother, the bond of a baby and parent.
"Okay," she acquiesces, kneeling (tiredly, her bones have ached more since Aang's passing) next to the wriggling infant. Her hands glow, and she examines the baby's tiny body.
"I can't find anything…" she mutters to herself, moving along to the infant's arm, wondering if she injured her shoulder whilst sleeping.
The baby grabs her finger, and Katara's whole heart stops. Just the same moment the baby stops crying.
And she feels it. The aura, the touch of her husband. On her shoulder, on her hand, her waist, inside every part of her. Katara's eyes fill with tears, and she picks up Korra and buries her face in the infant's new, round head.
"She is fine," Katara manages after a few moments, "just fine."
Senna and Tonraq come closer, concerned. "Are you alright, Katara?" Senna asks, touching her shoulder. "You're crying…"
Katara smiles, holding Korra comfortably now. "Aang." she says simply.
Tonraq and Senna share a look, and Katara's suspicions are confirmed. She had thought everyone around her was taking care not to mention her husband, lest she begin to cry again. Perhaps they will realize now to talk about him often.
"Your child is the Avatar," Katara promises, her eyes still shining with tears, but her face happy.
Senna and Tonraq are excited, but apprehensive, uncertain but in awe. Katara knows well what it is like to be in love with the Avatar; she can imagine being the parents of the Avatar will be quite an adventure too.
From that moment on, she loves Korra. As she grows, Katara spends more and more time with her. She is her Waterbending Master, just as she was Aang's, and Korra masters the element before she is five. Korra loves her, and embraces her often. Sometimes, Katara can feel Aang's arms around her, too, especially once Korra grows.
Now that Korra is older, and off on her own journeys, Katara doesn't need to be around her to feel her husband. Aang is with her always.