For the SOD at level 2 a fighter with good con (16) would need to roll a 12 to beat it. If the Commissar was able to get within 30 ft of a spell caster then the caster would probable have to roll a 15 or 16 (assuming 11 or 12 con), which is very overpowered at low levels. I could see it making sense at high levels but it would still be slightly overpowered, eventually any person will fail a save that it could conceivably be forced to make every round, especially if it is a low AC, low Fort caster type.