Hence, even though the Death Knights treated Lin Li as the Retribution Knight and became his subordinates, they did not have their pathway to becoming Retribution Knights cut off. However, it was still very difficult for them to be promoted to Retribution Knights. Throughout such a long period of time, only one Death Knight managed to become a Retribution Knight, while the others were stuck at the peak of level-19.
However, in order for all the Death Knights to be promoted to Retribution Knights, each one of them would need to have a large amount of soul fire, which was very difficult to find in Anril. Even if all the Undead creatures of the Shadowglen were destroyed, it would at most only allow three to five Death Knights to be promoted.