Thanks for all the suggestions. Here is the corrected creature, ready for action, I hope.
Shalthis who Serves; Advanced Anarchic Water Naga Sor9: CR 22; Size H; HD 31d8+186 + 9d4+54; hp 408; Init +1; Spd 30 ft, swim 50 ft.; AC 23, touch 9, FF 22; BAB +27/+22/+17/+12/+7; Grapple +42; Atk: +32/+27/+22/+17/+12 melee (3d6 + 8 plus poison, Bite); SA Poison, spells, Smite Law; SQ Darkvision 60 ft., darkvision 60 ft, immunity to polymorphing and petrification, resistance to acid, cold, electricity, fire and sonic 5, Fast Healing 1; SV Fort +21, Ref +16, Will +27; AL CN; Str 24, Dex 13, Con 22, Int 10, Wis 18, Cha 32.
Languages spoken: Aquan and Common
Skills and Feats: Concentration +27, Hide +7, Listen +8, Spellcraft +13, Spot +41, Swim +24; Alertness, Blind-Fight, Combat Casting, Great Fortitude, Lightning Reflexes, Maximize Spell, Silent Spell, Simple Weapon Proficiency, Spell Focus, Spell Penetration, Eschew Materials, Greater Spell Penetration, Arcane Strike, Close-Quarters Fighting, Extra Smiting, Eyes in the Back of Your Head.
Sor Spells Per Day: 6/9/9/9/8/8/8/7/4.
Spells Known: Acid splash, Alarm, Arcane eye, Arcane mark, Baleful polymorph, Light, Blink, Blur, Break enchantment, Chain lightning, Cone of cold, Dancing lights, Daze, Detect magic, Detect poison, Dimension door, Greater dispel magic, Displacement, Disrupt undead, Enervation, Feeblemind, Flare, Forcecage, Ghost sound, Glitterdust, Globe of invulnerability, Haste, Invisibility, Mage armor, Mage hand, Magic circle against law, Maze, Mending, Message, Mirror image, Moment of prescience, Open/close, Prestidigitation, Protection from arrows, Protection from law, Ray of enfeeblement, Ray of frost, Read magic, Resistance, Shield, Stoneskin, Touch of fatigue, Water breathing, Waves of exhaustion.
Possessions: 15 Gems (2000 gp, 0 lb), Earring of counterspells (4000 gp, 0 lb), Scarab of protection (necklace) (38000 gp, 0 lb), Skin of charisma +6 (36000 gp, 2 lb), Earring of force shield (8500 gp, 0 lb), Coins (0 gp, 0 lb).
Here's Shalthis who Serves, with full Power-up Suite Active:
Shalthis who Serves; Advanced Anarchic Water Naga Sor9: CR 22; Size H; HD 31d8+186 + 9d4+54; hp 408; Init +1; Spd 45 ft (base 30 ft), swim 50 ft.; AC 26, touch 12, FF 24; BAB +27/+22/+17/+12/+7; Grapple +42; Atk: +37/+32/+27/+22/+17 melee (3d6 + 8 plus poison, Bite); SA Poison, spells, Smite Law; SQ Darkvision 60 ft., darkvision 60 ft, immunity to polymorphing and petrification, resistance to acid, cold, electricity, fire and sonic 5, Fast Healing 1; SV Fort +25, Ref +21, Will +31; AL CN; Str 24, Dex 13, Con 22, Int 10, Wis 18, Cha 32.
Languages spoken: Aquan and Common
Skills and Feats: Concentration +27, Hide +7, Listen +8, Spellcraft +13, Spot +41, Swim +24; Alertness, Blind-Fight, Combat Casting, Great Fortitude, Lightning Reflexes, Maximize Spell, Silent Spell, Simple Weapon Proficiency, Spell Focus, Spell Penetration, Eschew Materials, Greater Spell Penetration, Arcane Strike, Close-Quarters Fighting, Extra Smiting, Eyes in the Back of Your Head.
Sor Spells Per Day: 6/9/9/9/8/8/8/7/4.
Spells Known: Acid splash, Alarm, Arcane eye, Arcane mark, Baleful polymorph, Light, Blink, Blur, Break enchantment, Chain lightning, Cone of cold, Dancing lights, Daze, Detect magic, Detect poison, Dimension door, Greater dispel magic, Displacement, Disrupt undead, Enervation, Feeblemind, Flare, Forcecage, Ghost sound, Glitterdust, Globe of invulnerability, Haste, Invisibility, Mage armor, Mage hand, Magic circle against law, Maze, Mending, Message, Mirror image, Open/close, Prestidigitation, Protection from arrows, Protection from law, Ray of enfeeblement, Ray of frost, Read magic, Resistance, Shield, Stoneskin, Touch of fatigue, Water breathing, Waves of exhaustion.
Possessions: 15 Gems (2000 gp, 0 lb), Earring of counterspells (4000 gp, 0 lb), Scarab of protection (necklace) (38000 gp, 0 lb), Skin of charisma +6 (36000 gp, 2 lb), Earring of force shield (8500 gp, 0 lb).
Invisible: Attacks with +2 melee, +2 ranged. 50% miss chance. Defender also loses Dex bonus to AC.
Hastened: Attacks with +1 melee, +1 ranged. AC +1 (Dodge). +1 to Ref saves. Speed multiplied by 2. One extra attack, +1 only in full attack action
Mage Armor: AC +4 (Armor).
Protection From Law: AC +2 (Deflection). +2 to saves. Only effective against creatures of the specified alignment.
Magic Circle Against Law: AC +2 (Deflection). +2 to saves. Only effective against creatures of the specified alignment.
Stoneskin: DR 10/adamantine. Max 150 hp absorbed
Blink: Attacks with +2 melee, +2 ranged. 50% miss chance. Speed
multiplied by 0.75. Half damage from area attacks only.
Item: Skin of Charisma +6: +6 to Cha.
Item: Scarab of Protection (necklace): SR +20.
Item: Earring of Counterspells (Greater Dispel Magic)
And here's a glimpse at one of her Shield Guardians:
Shield of Shalthis, Primus; Advanced Anarchic Shield Guardian; CR 20; Size H; HD 63d10; hp 376; Init +0; Spd 30 ft, Swim 60 ft.; AC 26, touch 8, FF 26; BAB +47/+42/+37/+32/+27; Grapple +70; Atk: +60/+60 melee (2d6 + 15/crit 19-20, slams); SA -, Smite Law; SQ Construct traits, darkvision 60 ft., fast healing 5, find master, guard, low-light vision, shield other, spell storing, darkvision 60 ft, immunity to polymorphing and petrification, resistance to acid, cold, electricity, fire and sonic 5, Fast Healing 1; SV Fort +21, Ref +23, Will +21; AL CN; Str 40, Dex 10, Con 0, Int 3, Wis 10, Cha 1.
Skills and Feats: Sense Motive +19, Swim +46; Alertness, Blind-Fight, Cleave, Combat Reflexes, Endurance, Improved Bull Rush, Improved Critical, Lightning Reflexes, Power Attack, Great Sunder, Athletic, Improved Sunder, Awesome Blow, Close-Quarters Fighting, Combat Brute, Hold the Line.
Possessions: None.
of course Color Spray was not the reason for the spell focus choice 
Was just to add a low-level enchantment to justify why she might have taken SF long ago. The spell also has no HD limit, and its only real problem is low DC, but with Heighten (if she had it) it could be useful. Otherwise let's just say that the naga uses it against the occasional low-level critters she may meet...
must be because nowadays with nerfed SF it doesn't happen to need to remember schools that often... yes this sounds like a good excuse for me 
