Obito understood. He understood better than Kakashi probably did. What his life was worth to Kakashi.

When he got crushed, he still had his eyes. But when he gave them away…Kakashi's Mangekyo activated when Obito died.

Or when he thought he did.

Kakashi was the only reason he was alive, and that was because he considered Obito the person he loved the most in the world. Obito had slipped through the rocks when they fell on him because that was the power of Kamui.

Obito came back to Konoha with an alive Kakashi and a dead Rin, and even when Kakashi couldn't bear to look at Obito, he still stayed beside him, and when Obito started feeling like he couldn't stand to stay in a world so empty, Kakashi would be beside him.

It was ironic that people didn't understand Obito when he felt like it was the most logical choice in the world. Kakashi would wake up from his nightmares and look for Obito. Sometimes Kakashi would rub and rub and rub his hands, trying to get the stain of Rin's blood out and Obito would hold his hands in his and stay as close to Kakashi as he needed to be.

Maybe they took 'codependency' to a new level, but Obito was the first thing Kakashi saw in the morning and the last thing he saw at night.

Sometimes, it would be different. Kakashi would run his hands through Obito's hair while they lay together. Obito would put his arms around Kakashi's waist, trying to fit them both on the small couch.

Sometimes…Obito would hold Kakashi's hands and kiss each fingertip slowly, and Kakashi would stare back with an unreadable look.

Sometimes, Kakashi would stand in the doorway and stare when Obito took off his clothes and then trace the line that separated the Hasirama cells from his real body with his eyes.

Sometimes, Obito would turn around and look back.

Nothing ever happened. But sometimes it felt like everything did.