I had a theory that the agent Sazed was looking for was going to be Kaladin. While nothing contradicts this theory (as the balance between protecting and killing is obvious), the evidence I thought I had turned out to be wrong or weak. The weak piece of evidence I have remaining is the glowing eyes. Kaladin's eyes glow yellow. We know colors associated with the shards on Roshar are blue for Honor, (as shown in the honor springs color and the tint of stormlight) Green for Cultivation (towerlight is more green and green is a nature-y color) and finally red for Odium(obviously red glowing eyes, color of voidlight ect). Yellow is not associated with any power hence my thought of an outside shard. Unfortunately my other piece of evidence was the voice who accepted Kaladin's fourth oath, but that was Dalinar not an outside force. Anyway just posting this to potentially say I called it, but if anyone has any other evidence or reasons why this is wrong let me know.