Ulcaster, please keep in mind that with that the 22 intel and 24 due to spellcasting progidy was before the headband. So he had a 30. It gave him tons of bonus spells, and raised the dc bonus to +10. Another +2 for it being shadow magic, and +2 more for the greater spell focus. The dc on his phantasmal killer spell at 8th level was 28. For most enemies who are not immune to illusion spells basically an automatic death. Undead opponents were not much better, even though they were immune to his magic sicne one of the players was a single class cleric, and another was a paladin.