He saw her the entire time. From the moment he awoke to the moment it was all over, all he could think of was her. She had been the driving factor, his motivation. Without her, was the world worth saving? He knew the answer was of course yes, but somehow knowing that she was a part of it made it all the more worth it. He looked back on the past months and realized how childish he had been. Yes, he had loved her, but he had never known how to show it. He laughed now at his attempts to woo her in the past. No wonder she had always seen him as a little brother. But he was a man now. He had to make her see him in this way.
He went to her on a warm late summer night. She was sleeping peacefully in a hammock on the porch of the house on ember island. He hair flowed gently with the wind, making her all the more beautiful. He brushed the hair out of her face, tracing his fingertips across her cheeks. She gave a small shudder but didn't wake. He smiled. He wondered what she dreamed of. He wanted to hold her while she slept and keep her safe in a way different than he had kept the rest of the world safe. He sat beside her and watched her, wondering how he would tell her in a way she would understand.
He couldn't. She had made it clear before that she didn't love him; or at least that she was confused. He didn't want to put that burden on her. She had already been through so much. He just wanted her happiness. He realized he had to let her go.
He leaned in and kissed her forehead gently, feeling her hair tickle his neck.
"I love you, Katara," he whispered. He stood up slowly and walked away, without looking back. He walked to the edge of the island, where the land met the waters. He stood there looking out over the world he was destined to protect. All he wanted was for the ocean to swallow him up again; to disappear forever.
"I love you too," she said as she grabbed his hand in hers.
They sat on the beach looking out at the waters as he held her in his arms until the sun rose.