Originally, Lu Sou, like the others, thought Duan Ling Tian was just bragging when he said he came to the Lu Clan to be a Revered Elder or an Interim Advisor.
The first thought in Lu Sou's heart was Duan Ling Tian would certainly die when he saw Duan Ling Tian had ignored the Lu Clan's Second Young Master's advice and resolutely killed the Lu clan's Third Young Master, Lu Huai.
When the Lu Clan's two strongest Guardian Elders appeared and confronted Duan Ling Tian about the death of Lu Clan's Third Young Master, Lu Huai and the Second Young Master Lu Bai failed in pleading for mercy, Lu Sou did not think Duan Ling Tian would survive.
However, the subsequent development of the matter was completely beyond his expectation.
When the Lu Clan's Guardian Elder, Lu Gui was about to kill Duan Ling Tian, Duan Ling Tian manifested a wisp of Pill Fire.
Violet Gold Pill Fire!
Grade one Pill Fire!
Author has been using Interim Advisor all the while but it seems he has begun using them interchangeably. We're following his RAWs which say Interim Elder temporarily but will be retconning it in the future should this change.