Zeratul couldn't have kill adun, if i remember correctly, they didnt even live in the same time bracket...
Zeratul was born in 1865 (sry for my previous mistake)
Adun died in the 1500s
Raszagal was born in 1456 and later on was killed by zeratul on char in 2501 because kerrigan infested her.
At 1,045 years of age, she was one of the oldest living protoss, and of the Dark Templar. She was one of the few old enough to clearly remember Aiur from before their exile.
Taldarin is not 3000 years old, it was a mistake of lore in the game:
Though Taldarin says that he fought with Adun three thousand years ago, the actual timeframe is much shorter; Chris Metzen blames this on the timeline not having been firmly pinned down when the mission was written.