REQUIREMENTS
1. OBSE (xOBSE v. 22.6.1)
2. Shivering Isles DLC

Don't try running the mod without those, it probably won't even load. And even if it does, half of the functions won't fire.
Milchar's Curse was created with OBSE 22.6, but it's possible that older versions of OBSE are safe to play & run.

HOW'S THIS?

FEATURES

• Summon your alter-ego from Vaermina's realm of nightmares to fight by your side.
• Lasts for almost five minutes.
• Base health value is yours times two.
• If your clone dies before Body-Split ends, they'll "give back" half of your health and fatigue.
• Will unconditionally side with you if you're the aggressor or the criminal.
• Will swim and jump while following you.
• Weather will slowly transition to a "hellish red", so powerful is the process to set apart the soul.
• No Save Bloating, as I scripted a safe way to completely delete the copy after disabling it.
• All player restrictions are lifted once the effect ends.
• Slightly better than a bethesda summon since the Shadow follows you into different worldspaces.
• Lore-friendly.
  

SETBACKS

• Requires conjuration skill of 100 (Master).
• Half of your health and fatigue will be taken to create your Shadow.
• Extremely high magicka cost. (300 Magicka per cast at 100 skill level).
• The Doppelganger cannot be interacted with.
• The Doppelganger has half your running speed.
• Your magicka will not regenerate, as the shadow requires constant consumption of the subtracted value.
• You won't be able to fast travel while the spell effect is active, as no vanilla summon follows you if you teleport through the map.
• Waiting while splitting your body is impossible.
• Sleeping while splitting your body is impossible.
• Out of combat the clone will tolerate two hits before turning on you.
• Body-Split nerfs conjuration skill at -85 points to prevent the player from interrupting the spell effect & script loops. If you somehow manage to lift the absurd magicka restriction and summon a second doppelganger while the first one is active, one of them will simply disappear.
• You cannot activate the Strange Door while the effect is active.
• If your clone is killed and your health regained, restrictions won't be lifted until magic effect ends. Consider that an extra penalty for your S-rank summon.
  

CONDITIONS

• Quest will trigger after the Font of Madness becomes unresponsive.
• AND You must be in the Shivering Isles.
• OR You're a Daedric Prince.
  

Saves between stage 20 of "The Roots of Madness" and below stage 6 "The Prince of Madness" will not initiate Milchar's Curse. Specifically:
(Roots of Madness stage must be equal to 10 OR "The Prince of Madness" stage must be greater or equal than 6)


DEMO

•  If you'd like to try the spell before keeping it, open the console and type:
  

CenterOnCell TestingHall
If you're on the testing cell the quest should trigger automatically, adding the spell to your inventory. Wait 5 seconds before the next stage update to receive the spell.

To leave the testing hall simply type and hit enter:
CenterOnCell KvatchChapelofAkatosh    (if you're not in the Shivering Isles)
CenterOnCell SEGreetingRoom(if you're in the Shivering Isles)


NOTES

• Parameters were coded in disregard to cheats (ex: GodMode). If you use cheats like 'GodMode' or set your conjuration skill above 100, the script may behave unpredictably.
• Sometimes NPCs will try to chat with your Shadow creating a silent loop in their AI's behavior. Simply talk to the NPC who activated your summon, exit his dialogue and the Doppelganger should follow you once more.
• A secret timer kills your Shadow a few seconds before Body-Split effect ends. I tested this function extensively, but if the spell is nearing its end and you don't see your clone getting automatically killed and faded into invisibility, then something is wrong.
• When summoning the shadow, it's advisable to wait a few seconds before it's fully "faded-out" and has its dark shader fully loaded. Speaking with it as it fades will result in a "I HAVE NO GREETING" line.
• The Shadow is supposed to only equip your current armor and Shadowrend. Testing confirmed that. If by any chance it equips something else when (let's say) you get through a loading screen or a new area is loaded, please report.
• The Shadow is supposed to fight only with Shadowrend/ShadowAxe and a few healing spells plus some other spells you may have learned. It's not supposed to use any conjuration spells. Unfortunately, the script was killed when I tried to remove a DLCTomes spell from the clone. If you have one of those DLC spells in your inventory and don't want the Doppelganger to cast it, consider having that spell deleted with Wrye Bash or remove its formId via console.
• Body-Split will certainly be among the most powerful creature summons of your game, as the shadow copies your current level, skills, stats and always equips the deadliest weapon, Shadowrend.
• Shadow strength may vary. During testing, I found it to be an absolutely overwhelming boss to any enemy.
• Sound FX will drop as soon as the player changes cells or worldspaces (function limitation).
• In order to include a more powerful function, I'd have to require an OBSE sound plugin just for this silly script.
• If Shadow Sound FX doesn't break its loop after Body-Split ends, simply reload your game or enter a different interior/exterior space.
  

LOAD ORDER

I honestly have no idea. I have my plugin loading at position 15, right after "Oblivion.esm" and "DLCShiveringIsles". If there's any problem regarding loading order, please report.

SPECIAL THANKS AND CREDITS

To AsteriaSennall for cleaning the plugin with TESEdit.