Sage Kindness is an elderly man employed by Vencarlo Barsavi seemingly for the sole purpose of torturing people during Barsavi's interrogations. He is first mentioned by Sanza when Locke goes to pay his tax to Barsavi. Locke walks in on Barsavi interrogating the full crowns and bears witness to Sage Kindness' actions.
He appears to be near emotionless and/or sadistic
One method mentioned is when Kindness smashes some glasses to pieces in a sack, then proceeds to place this sack over a Full Crown's head and knead the glass into his skull. The man is left with a dripping mass of blood where his head was