Yep. Of course, it takes a full day to make an Arrow of Death, and the archer can only have one such at a time, and the Fort DC is only 20. As it is a scoch difficult to get both a BAB of +6 and arcane spells before about 7th, and the Arcane Archer doesn't get an Arrow of Death class level until 10th, so you are talking a loose minimum of a 17th level character. Without any con or save boosts (which is unlikely for something as important as Con and the Fort save), someone with poor saves is going to have a +5 modifier, and thus a 30% chance of beating the death attack (succeeds on a roll of 15, 16, 17, 18, 19, 20). Someone with strong saves (and again, the unlikly "no other modifiers") is going to have a +10; which translates to a 55% chance of beating the death DC. Throw in a +6 con item and a luckstone, and the poor save fellow has an even 50/50 chance, while the strong save fellow has a 75% chance of surviving a hit. A cloak of Resistance can make the strong save fellow nearly immune, as can a high base con. No, not overpowered at all - that aspect, anyway. It's Imbue Arrow at 2nd that can cause some real headaches....