Near

You knew Near since he was little, you grew up together in Wammy's House, although he was distant you always stayed by his side. When the Kira case happened, after L died and Near became his successor, you stayed at Wammy's. When Mello left the orphanage, you followed him with the intention of finding Near and staying by his side again. And so it happened after Mello discovered where Near was, you accompanied him, you stayed with Near until the end of the Kira case. You stayed by Near's side the whole time and they live together at your request, Near didn't care. Matt and Mello had died, now Near is 27 years old and is solving a different case, you are waiting lying on the sofa eating some candy until you are assigned another case to solve.