The Empyrean uses CHA as its spellcasting ability having a Mod of 8 and a Save of 8. Let's say the Empyrean must make a WIS save -- that's (d20+13). But the Empyrean's Spell Attack Bonus would be +8 instead of +13 because Charisma is the spellcasting ability, not Wisdom. Is that an example?
Yes, that's a good example of a creature that is not proficient in saving throws with the ability it uses for spellcasting.
It's proficient in Wisdom saves, so its Wisdom saving throw modifier is +13 (6 for its Wisdom modifier plus 7 for its proficiency bonus). It is not proficient in Charisma saves, so its Charisma save modifier is +8 (just the 8 from its Charisma modifier with no proficiency bonus).
The Empyrean's spell attack bonus is +15: 8 from its Charisma modifier and 7 from its proficiency bonus. (In practice, its spell attack modifier does not matter as it doesn't have any spells that use attack rolls.)
No spells that use attack rolls -- that's another interesting point.
It's not much of a stretch to imagine that an immortal would have acquired an array of interesting magic items -- ones that can be used to store and cast spells. Scrolls have Save DCs that are assigned by spell level, so that is well defined. An Empyrean using a scroll -- I think that is within the rules and might not affect its CR of 23. But now the Empyrean picks up a Staff of Power. Its AC would jump from 22 to 24 and his spell saves and attacks would also receive a 2 point advantage. Are monsters allowed to employ magic items? Do the affects of magic items "stack" if it decides to hold two attuned Staffs of Power?
No spells that use attack rolls -- that's another interesting point.
It's not much of a stretch to imagine that an immortal would have acquired an array of interesting magic items -- ones that can be used to store and cast spells. Scrolls have Save DCs that are assigned by spell level, so that is well defined. An Empyrean using a scroll -- I think that is within the rules and might not affect its CR of 23. But now the Empyrean picks up a Staff of Power. Its AC would jump from 22 to 24 and his spell saves and attacks would also receive a 2 point advantage. Are monsters allowed to employ magic items? Do the affects of magic items "stack" if it decides to hold two attuned Staffs of Power?
Yes, monsters are allowed to employ magic items. A Staff of Power specifically has class requirements for its attunement, and an Empyrean doesn't have a character class and therefore can't meet those requirements. However, since the behavior of monsters is generally up to the DM and they don't always need to follow the same rules as player characters for how their abilities are constructed, there's no reason an Empyrean couldn't have a magic item that grants a bonus to spell attacks or spell save DC.
As for your last question, it's not possible to attune to more than one of the same magic item at a time.
Yes, that's a good example of a creature that is not proficient in saving throws with the ability it uses for spellcasting.
It's proficient in Wisdom saves, so its Wisdom saving throw modifier is +13 (6 for its Wisdom modifier plus 7 for its proficiency bonus). It is not proficient in Charisma saves, so its Charisma save modifier is +8 (just the 8 from its Charisma modifier with no proficiency bonus).
The Empyrean's spell attack bonus is +15: 8 from its Charisma modifier and 7 from its proficiency bonus. (In practice, its spell attack modifier does not matter as it doesn't have any spells that use attack rolls.)
pronouns: he/she/they
No spells that use attack rolls -- that's another interesting point.
It's not much of a stretch to imagine that an immortal would have acquired an array of interesting magic items -- ones that can be used to store and cast spells. Scrolls have Save DCs that are assigned by spell level, so that is well defined. An Empyrean using a scroll -- I think that is within the rules and might not affect its CR of 23. But now the Empyrean picks up a Staff of Power. Its AC would jump from 22 to 24 and his spell saves and attacks would also receive a 2 point advantage. Are monsters allowed to employ magic items? Do the affects of magic items "stack" if it decides to hold two attuned Staffs of Power?
Yes, monsters are allowed to employ magic items. A Staff of Power specifically has class requirements for its attunement, and an Empyrean doesn't have a character class and therefore can't meet those requirements. However, since the behavior of monsters is generally up to the DM and they don't always need to follow the same rules as player characters for how their abilities are constructed, there's no reason an Empyrean couldn't have a magic item that grants a bonus to spell attacks or spell save DC.
As for your last question, it's not possible to attune to more than one of the same magic item at a time.
pronouns: he/she/they
Thank you wagna.
No class assignment -- that's another interesting point.
Monsters do not have class assignments, so they cannot employ magic items that have class restrictions. Is that your understanding?