What does it do?
In simple words
It adds a lesser power that consume a Dragon soul to get temporary and permanent bonuses.

I tried to mimic Miraak's power when he consumed a Dragon souls to heal himself. Since a Dragon soul is "rare" and fully healing you would have been equivalent to taking a "cheap" health potion, I decided to spin off the power a bit to make it more appealing but still balanced.

Temporary bonuses

• Increase health, magicka and stamina regeneration rate by 1000%. 1000% might appear a lot, but most Heal spells will outperform this.
• Reduce cooldown between shouts by 100%. Free shouting to your heart's content for a limited amount of time.
  

Permanent bonuses

• Increase health, magicka and stamina regeneration rate by 2%/Dragon soul consumed.
• Reduce cooldown between shouts by 1%/Dragon soul consumed.
  

Limitations

• Temporary bonuses last for 30 seconds. Less than that and it feels like you don't have time to use it. More than that and it feels like a bit too much.
• Temporary bonuses don't stack with a second cast while the power is still active. Duh! It would have been way overpowered to allow such a thing... If you recast the power while it's still active, you only reset the duration to 30 seconds and consume a Dragon soul for your efforts, not your greatest deal...
• Permanent bonuses top at 25 Dragon souls consumed. This means the permanent bonuses will never be greater than 50% health, magicka and stamina regeneration rate and 25% reduced cooldown between shouts.
• You can't use the power if you don't have a Dragon soul. You also need those Dragon souls to unlock shouts, so be careful before spamming this power
• Not as efficient at lower levels. Since the efficiency of regeneration rate is directly tied to your maximum health, magicka and stamina, you're limited by the amount you have and to a limited extent by your level. As you level up, you gain more health, magicka and stamina which in turn will make the power better (7%/second of 100 HP is much lower than 7%/second of 500 HP). The goal was to balance the power for all levels.
  

Installation, requirements and compatibility
Requirements
Latest version of Skyrim Special Edition

Install (auto)
For an automatic install without risk of errors, I suggest you use the NexusModManager.

Install (manual)
For a manual install, extract the files from this mod and copy them to the appropriate folders.

Uninstall
Open the console and type: SetStage TTR_Ziil_Los_Dii_Du 100. Save and uninstall the mod manually or with your mod manager. I'm not sure the SetStage is still necessary. In the past, there were some CTD when you deactivated an ESP with a spell already learned by the player. I've tried to reproduce this on my game but wasn't able to. I'm putting it here as the "safest" method just in case you need it.

Compatibility
Compatible with everything.

F.A.Q.
Why isn't this a shout?
I've receive multiple requests to make this as a shout so let me explain why I didn't.

The scene with Miraak saying those words is just a scene, there is no audio for those words. The only ressource for audio would be Miraak saying the line. Even if you put aside the fact you would hear Miraak's voice when shouting, the problem is it would be illegal from a copyright point of view to edit the original audio and repack it under a mod. Not to mention the mod would be removed from the Nexus and I could be banned. So audio is out of the picture.

The words Ziil Los Dii Du have no art/graphic either. I could use other symbols, and I'm sure I'd have some lore zealot to remind me they don't match, but there's also the fact the "shout" is 4 words instead of 3. That means the CK cannot handle it and neither can the in-game UI. So technically, graphics are out of the picture too.

While I agree this would have been really epic, what are we left with in reality if you don't have audio and graphics to support the idea? I'd say you have to think outside the box a little. Technically speaking, a shout is 3 words. When Miraak uses his "power", he uses 5 words (DragonName, Ziil Los Dii Du) and they are subtitled like any normal dialogue. It wouldn't be that far fetched to consider this more like a "sentence" in dragon's tongue than a shout. With that said, it open up the possibility the effect came from something else and since a lesser power only available to the Dovahkin could fit the bill, that's the way I decided to go about it. It's not perfect, but it's as good as it can be within the realm of reality.

Known issues
None. Although, as with any shout or spell, trying to cast the lesser power twice in a row in a very short time will not work. Technically, there's a "cooldown" of more or less 1 second for the animation to play even if there isn't one. It's an engine problem but I don't see why you'd want to spend 2 Dragon souls to add 0.5 seconds to the spell's duration...

My other mods

• Master Trader SE - Merchants never run out of gold
• Mod Publishing Tutorial - Everything you need to know to publish your mod and make your mod page right
• Oghma Infinium - A portable training station without the nonsense
• TheThirdRace Skill Overhaul - Minimalistic and modular skill overhaul aimed at balancing the vanilla skills while maintaining the vanilla feel