Echo Again, by Splay, is the third ending to Katekyo Hitman Reborn!, and is used from episodes 30-38.
The moon shines through my window
from between the tall skyscrapers
I tried reciting aloud
the letter you sent me from so far away,
When I close my eyes, I can see you
for an instant as you say goodbye
Enduring the nights, I long to see you more.
Wanting to touch you more...
You're the only one who can erase
the darkness inside me
All I can tell you, I'm sure
I DON'T WANT TO MISS YOU ANYMORE
The more I long for you, the more it ECHO(es} AGAIN
- This ending was only used for 9 episodes, shorter than the usual 13-26 for most anime endings.