Cadal Timeline and Summary

Cadal becomes Merlin's servant right after Merlin arrives at Ambrosius' house in Brittany.
Cadal follows Merlin into the creepy forest (after Belasius), even though he warns Merlin that there will be trouble.
Cadal waits on the path for Merlin's return and sees that he's been taken by Uther.
Cadal accompanies Merlin back to Wales and poses as a (silent) Cornishman. He helps Merlin erect a barrow over Galapas' bones.
When Merlin is kidnapped, Cadal follows him to Vortigern's court and serves him.
Cadal, Merlin, and Gorlois head back south to Maridunum. He stays on to gussy up the cave while Merlin joins Ambrosius.
After Ambrosius' burial, Cadal and Merlin return to Stonehenge at the winter solstice to honor the king.
Cadal follows Merlin to Uther's coronation and gets the 411 on the Ygraine situation.
At Tintagel, Cadal minds the horses while Uther and Merlin head up to the castle.
Things go wrong, and Cadal is attacked by Brithael's servant. He kills his attacker but is also mortally wounded.
Cadal surprises Merlin by speaking to him one last time.
After Merlin promises to keep Cadal's legacy alive, Cadal dies.