Flooded Caverns · area boss

Xanthir Mor, the Deep Archmage

the Deep Archmage

A named threat of Flooded Caverns, encountered rarely and never in numbers - real Dungeons & Dragons statistics, no auto-computed shortcuts.

CR 21 Undead · Wizard 16 / Archmage 5 resref fc3_xanthir

Stat block

STR
10
+0
DEX
14
+2
CON
16
+3
INT
22
+6
WIS
12
+1
CHA
14
+2
Hit points
168
Natural AC
3
Skills
Concentration 20 · Lore 15 · Spellcraft 24
Feats
Toughness, SkillFocusSpell, SpellFocusEvo, Alertness, IronWill, feat_epic_spellcasting, FEAT_EPIC_SPELL_MAGE_ARMOUR

Prepared spells

LevelKnown / Prepared
1Magic Missile
2Gust of Wind
3Haste
4Improved Invisibility
5Poison
9Epic Mage Armor

Combat sequence

Layered on top of the module's own combat AI, which still picks targets and positioning. The fight below moves through real hit-point-gated phases; every save DC and attack bonus computes from the stat block above at runtime.

I

Archmage's Bolt

Every round, the same spell throughout

He never changes what he casts - only how.

II

Empowered, then Maximized

85%, then 65% hp

The bolt's own roll is bettered, then simply maxed outright.

III

Extended, then Quickened

45%, then 25% hp

A lingering tail joins the bolt, and below a quarter health it fires twice a round.

Why these numbers

CR 21 is set against Flooded Caverns's own real ambient ceiling, not auto-computed from level alone - a genuine Wizard 16 / Archmage 5 build at 21 total levels.

Hit points (168) follow this project's own average-hit-dice convention, and every save/attack bonus derives from the ability scores above at runtime - nothing here is hardcoded past the phase gates themselves.

How it's wired

Boss-flagged (bypasses the drop-rate roll, two loot-generation passes) and gated to a single spawn - only one Xanthir Mor is ever up in Flooded Caverns at a time.