An NX port of Final Fantasy Serah Farron Follower created by Dragonflame17.
You can find her sister, Lightning at  Final Fantasy XIII Lightning Follower NX  .
Fixed tons of bugs, and merged all needed files into 1 esp. You won't have to install so many esps. Just one file.
2020/2/20 UPDATE 1.2.0: Bodyshape changed to make her near the original look. A little adjustments on her face. Clipping fix. Loose files packed. Strongly recommend to update.
This mod includes (with permission):

• Final Fantasy Serah Farron Follower by Dragonflame17 (with dark face bug fix, texture mismatch bug fix, useless data cleaned and SSE optimized)
• Final Fantasy 13 2 Serah Weapon Starseeker by Prorat99 (with NPC usable adjustment and SSE optimized)
• FF13 塞拉shala`衣服```（玲玲作品） by qqqwwqa from 3DMGAME (Serah's outfit, with SSE optimized)
• UNP Female Body Renewal - A female face and body replacer by dimon99-hello santa-Reize-Shiva182 (for Serah's built-in skin)
  

The following description is based on the oldrim version.
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Serah can be found in the Temple of Kynareth in Whiterun. She acts just like any other follower, and but has character specific spells available to her (listed below). She can be married. I highly recommend using UFO (Ultimate Follower Overhaul) UFO SE (Use Special Edition instead) as it allows you to turn off her magic if you're so inclined, as well as customize her inventory (and that's just the beginning!) (Serah's Outfit is already included, it's not recommended to change her outfit, or you may encounter clipping issues). Should you have any problems, be sure to include them in the comments.

Spell Data
I based her base spells off of her roles in Final Fantasy XIII-2 (Commando [not applicable to magic], Ravager, Sentinel). With that in mind, she uses:
- One handed Incinerate (Ravager)
- One handed Lightning Bolt (Ravager)
- One handed Ice Spike (Ravager)
- One handed Ebony Flesh (Sentinel)
- One handed Fast Healing (Just for convenience)
Why are these all one handed you say? Well, since she uses the Spellsword combat AI, she'll always dual wield a regular spell. Considering Prorat99's rather appropriate weapon exists(Already included), I think it's more appropriate for Serah to be able to wield both a sword and magic (and not entirely magic)

Required Mods:
You just need Beautiful Hair Retexture 1.3, which was on this page, but has since been removed.It can now be found here.
None

Load Order:
1. Beautiful Hair.esp
2. Lightningrace.esp
3. Serah Follower.esp (THIS MUST BE BELOW THE OTHER TWO)
Only one Serah.esp needed

Recommended Mods: (Don't download the striked mods on SSE!)
Calientes Female Body Mod
Covereyes
Face data used for screenshots
Serah's sister; Lightning
Lightning's face preset; compliments of Rambobrill
Some common problems:

Q: Why does her hair turn black in some environments? (Already fixed)
A: That's because of the hair files, it's not something I can fix

Q: Why is there a neck seam! (Already fixed)
A: Serah will use whatever face mods you use. I'm entirely sure if her body uses the same body as you do, but the neck seam has been remedied by some body texture replacers (CBBE comes to mind)

Q: Why doesn't she look like she does in the game! You're an awful replicator!
A: Sheesh that was harsh. I tried my best to make it as close to the pictures I was able to find of her. I can't be 100% accurate because the default body parts (specifically the eyes) aren't nearly close enough to the original

Q: Can I find her clothes/weapons anywhere? I saw that you had them in the screenshots! (Already fixed)
A: Why yes you can. A quick google (hehe, maybe not quick) search can help you find them. I've already linked Prorat99's sword. Needless to say, you may need to wade through some japanese sites to find what you're looking for *cough*modtype*cough*

Q: Why do I need to download Beautiful Hair? Can't it just be included in this mod? (Already fixed)
A: Yes it could have. But it isn't. On the bright side you can enjoy being a bulky orc warrior with cute pink hair.

Troubleshooting:

Got a CTD? (Already fixed)
1. Did you check the load order?
2. Did you download Beautiful hair (link is above)

Does Sarah have greyish/white hair color? (Already fixed)
1. This is a conflict with my Lightning follower. To fix this, your load order needs to look like this:
lightningrace.esp
lightning follower.esp
serah follower.esp
lightning race vampire.esp
2. Give HighDragonSlayer a cookie for finding the fix!