That being said Alexander's death on his 18th birthday was the factor controlling and defining and looming over Alexander in KQ3 and was brought up in all the later games synopses as you might remember?
It was the whole entire purpose of the short story in the manual in KQ3 as well.
On another note, Abdul Alhazred attempted to have Alexander killed on multiple occasions. Of course Shamir never tried to do it directly (except in the end battle).