From A Wiki of Ice and Fire
Lum is a guard in service to House Lannister.
A Storm of Swords
Lum is one of the guards who are guarding the apartments of Lord Tywin Lannister, the Hand of the King, in the Tower of the Hand the night Tyrion Lannister sneaks inside and kills Tywin.
A Feast for Crows
When feeling a call of nature, Lum finds Lord Tywin Lannister dead on the privy.
- ↑ A Storm of Swords, Chapter 77, Tyrion XI.
- ↑ A Feast for Crows, Chapter 3, Cersei I.