Katara smiled as she gave Rohan back to Tenzin. She remembered the hope that the birth of Tenzin gave her and so she acknowledged that feeling when handing the small child back to his father.
She was no longer the midwife she once was back in the southern water tribe but rather a fully powerful healer with much experience; Most of which was shown in her hands and in her body frame as she recognized the familiar feeling of her back being hunched over and as she looked at her frail hands
She sighed as she saw Tenzin and his family walk back to their house in the modern version of the southern water tribe. She missed her family. But most of all she missed her husband. A single tear fell down her cheek as she cried silently to herself "I don't want to go Aang". Her voice beginning to tremble and her eyes producing more tears. "I'm not ready to leave them yet" Katara managed to get out before breaking down into a fit of sobbing.
After a while she regained her lost composure and wiped away the tears. She hadn't come to terms with her looming departure but she knew she couldn't prevent it any longer lest she would leave right there in the tundra.
The sun now set Katara made one last glance at the clearly visible southern lights and recognized the spirits that now freely danced upon them. She was happy that Korra had finally reached her avatar potential and so she showed the spirits her approval with a smile.
She then walked as fast as her body would let her into her house. She slowly got ready for bed and then kissed her picture of Aang goodnight. She looked in the mirror one last time; she wanted to see the body she lived in for all these years. She scaled her aged body from head to toe to head again, paying most attention to the many wrinkles she had.
She finally climbed into bed. Her 87 years of life running through her head. From the days she fought the fire nation to her days as the avatar's wife. She thought about all the friends she'd made along her journeys throughout the world and how she was last to leave the realm of the humans.
Her thoughts went from the least important people in her life to the most, her last few thought were of her husband and her children. She thought about Meelo and Rohan who would grow up barely knowing her. She thought about Jinora and Ikki and how they would feel. She felt horrible for leaving them all like this so suddenly just when everything was beginning to look bright again and the world was beginning to settle back into its fairly new routine of peace.
She thought about Kya, Bumi and Tenzin and how they would deal with it. She began to fall into a deep slumber and so with her last amount of remaining consciousness she wished them a happy and peace fulfilling life. She then thought only of how much she loved them as she drifted off to sleep.
During her sleep Katara took her last few remaining raspy breaths. She was gone. She was 87 and the last remaining member of team avatar. Her family members would wake up to find that their beloved mother and grandmother has died. They would be filled with a deep sense of loss and despair because Katara was their hope; the glue that kept them all together. She never turned her back on the people who needed her; something she was admired for all throughout her lifetime. Something that she would be admired for throughout her life in the world beyond what they could comprehend as the world of the physical beings.