What the heck is this guy? He's practically impossible! When I enter the area, he is hasted, has spell turning, then mirror images and pro. magical weapons immediately, followed by a quick cast Death Fog then rushes my spell casters and starts swinging away at like 7 attacks per round! Plus, he seems to have some acid, fire, cold, something damage with his weapon, cause my stoneskined/ironskined spell casters still take damage when he swings. Plus, he can automatically slow people and hit others with a special Melf's acid arrow!!!!

Why is he in the game now (I have mods, see below) and is there any way to defeat him or must I just give away my great katana because some jerk thought that it would be smart to mod that in?
Sorry if the spelling or grammar are tough to follow, I'm really upset (fought him like 12 times).
// Log of Currently Installed WeiDU Mods
// The top of the file is the 'oldest' mod
// ~TP2_File~ #language_number #component_number // [Subcomponent Name -> ] Component Name
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #0 // BG2 Fixpack - Core Fixes
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #1 // BG2 Fixpack - Game Text Update
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #2 // Super Happy Fun Lucky Modder Pack
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #100 // Party Gets XP for Sending Keldorn to Reconcile With Maria
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #102 // Cromwell's Forging Actually Takes a Day
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #104 // Ghreyfain's Holy Symbol Fixes
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #105 // Additional Hero Quests in Trademeet Wait Until Hero is Officially Named
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #106 // Giants Receive Penalties When Attacking Halflings, Dwarves, and Gnomes
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #107 // Remove Dual-Classing Restriction from Archers and Stalkers
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #108 // Remove Second Attribute Bonus for Evil Path in Wrath Hell Trial
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #109 // Corrected Summoned Demon Behavior
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #110 // Additional Script Fixes
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #111 // Bard Song Fixes
~BG2FIXPACK/SETUP-BG2FIXPACK.TP2~ #0 #112 // Wizard Slayers Cause Miscast Magic on Ranged Attacks
~SETUP-SOS.TP2~ #0 #0 // Shadows Over Soubar, v1.11
~SETUP-SOS.TP2~ #0 #1 // Remorhaz walking speed adjustment (for ENGLISH version .EXE ONLY!!!)
~SETUP-TDD.TP2~ #0 #0 // The Darkest Day, v1.11
~SETUP-CTB.TP2~ #0 #0 // Check The Bodies, v1.8
~SETUP-CTB-CHORES.TP2~ #0 #0 // Candlekeep Chores, v2.0
~SETUP-TS-BP.TP2~ #0 #0 // TORTURED SOULS v6.09 (BP Compatible Version)
~SETUP-BPV177.TP2~ #0 #0 // Big Picture AI/Enhancement Mod, version 177 weidu (beta)
~SETUP-BPV177.TP2~ #0 #1 // Improved Suldanessallar
~SETUP-BPV177.TP2~ #0 #2 // Improved Spellhold
~SETUP-BPV177.TP2~ #0 #3 // Wand of Orcus Add-In
~SETUP-BPV177.TP2~ #0 #4 // Improved Small Teeth Pass, by Kensai Ryu
~SETUP-BPV177.TP2~ #0 #5 // Improved Kangaxx Encounter, by Kensai Ryu
~SETUP-BPV177.TP2~ #0 #6 // Kensai Ryu's Improved Crypt King
~SETUP-BPV177.TP2~ #0 #7 // Kensai Ryu's Gnome Fighter/Illusionist in the Docks
~SETUP-BPV177.TP2~ #0 #8 // Improved Random Encounters, by Gebhard Blucher and Kensai Ryu
~SETUP-BPV177.TP2~ #0 #9 // Gebhard Blucher's Lich in the Docks
~SETUP-BPV177.TP2~ #0 #10 // Red Badge, Poison-Based Encounter, by Westley Weimer
~SETUP-BPV177.TP2~ #0 #11 // Kuroisan the Acid Kensai, by Westley Weimer
~SETUP-BPV177.TP2~ #0 #12 // The Ritual, by Westley Weimer
~SETUP-BPV177.TP2~ #0 #15 // Ascension for BP
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #40 // Change Viconia's Skin Color to Dark Blue
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #60 // Weapon Animation Tweaks
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #70 // Icewind Dale Casting Graphics (Andyr)
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #100 // Commoners Use Drab Colors
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #110 // Icon Improvements
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #130 // Force All Dialogue to Pause Game
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #1010 // More Interjections
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #1020 // Alter HP Triggers for NPC Wounded Dialogues
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #1070 // Improved Kick-out Dialogues
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #1080 // Add Bags of Holding
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #1120 // Stores Sell Higher Stacks of Items
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #1150 // Shapeshifter Rebalancing
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #1160 // Multiple Strongholds (Baldurdash)
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #1180 // Female Edwina
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2010 // PnP Spell Progression Tables
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2020 // Two-Handed Bastard Swords
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2030 // Two-Handed Katanas
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2040 // Universal Clubs
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2050 // Description Updates for Universal Clubs Component
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2060 // Weapon Styles for All
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2070 // Druids Use Cleric Level and Spell Progression
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2080 // Delay High Level Abilities
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2090 // Change Experience Point Cap -> Remove Experience Cap
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2100 // Allow Thieving and Stealth in Heavy Armor
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2110 // Alter Item Descriptions for 'Stealth and Thieving Abilities in Heavy Armor' Component
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2150 // Wear Multiple Protection Items -> P&P Restrictions
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2160 // Alter Weapon Proficiency System -> Rebalanced Weapon Proficiencies
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2192 // Limit Ability of Storekeepers to Identify Items -> Hybrid of Both Methods
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2200 // Multi-Class Grand Mastery (Weimer)
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #2210 // True Grand Mastery (Baldurdash)
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #3031 // Easy Spell Learning -> 100% Learn Spells and No Maximum Cap
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #3060 // Remove "You Must Gather Your Party..." Sound (Weimer)
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #3181 // Romance Cheats -> No Gender/Racial Requirements for Romance, Allow Multiple Romances
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #3200 // Sellable Staffs, Clubs, and Slings (Icelus)
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #4010 // Improved Fate Spirit Summoning
~BG2_TWEAKS/SETUP-BG2_TWEAKS.TP2~ #0 #4020 // ToB-Style NPCs