50,000 years ago, Hell was destroyed because of too much Foul from the resentment of the souls that later turned to Soul Eaters and devoured everything in their wake, leaving nothing of Hell. The gods above in Heaven, in order to take care of the newly-died souls, created the Afterlife Department comprised of grim reapers. Huo Ling was delivering food that day when he met Yi Bing and the guy gave him a warning. When he arrived to the customer's unit, he was killed. Huo Ling: you set up a death flag for me! Yi Bing: I'm a grim reaper. I'm the flag myself. Let me help you solve the mystery of your death. Huo Ling: your sister! Alternative title: The Different Ways I Died at 23 Update: daily
City of the Dead.
"Huo Ling." Yi Bing called as they ate.
"Yes?" Huo Ling answered as he chewed on the meat.
"Where is your next assignment?" Yi Bing asked.
"Hm? My next assignment?" Huo Ling wiped the sauce in the corner of his lips. "Why do you ask?" he asked.
Since Huo Ling is Yi Bing's apprentice, Yi Bing can see Huo Ling's next assignment and anything in Huo Ling's Death Note. This is the masters' privilege, and also a responsibility as the master since he still needs to supervise Huo Ling as his apprentice.
This lack of privacy made the other grim reapers dislike being an apprentice, especially if they would encounter a master that uses this privilege of theirs in a perverse way, like stealing their apprentice's points, etc.