[@Timemaster] Honestly you really don't have a lot of info or lore to work with and really make something but I'll do my best.

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[h2]Codex: Chosen of the Creator[/h2]
[i]Few are more blessed than the children of the Creator for unlike many gods, she walks with her mortal followers. Her gifts of knowledge and gene editing has given rise to a devoted crusading host of unparalleled faith and strength. Her followers are vast and her gifts are generous. Burn away the darkness of unbelief and set alight the torch of the Creator. Ashevelen be praised![/i]
[h3][u]Special Rules[/u][/h3]
[list][*][b]Favored of the Goddess[/b] - Units with the Enhanced rule treat units with the Rejected rule as expendable and do not suffer morale penalties when they flee or are wiped out. All units also get to take mutations from the Creator's Gifts table; Enhanced can take 1 while Rejected can take 2.
[*][b]Enhanced[/b] - Models with this rule get a 6+ Regeneration roll, restoring 1 wound after damage calculation.
[*][b]Rejected[/b] - Models wit this rule gain Frenzy and can reroll charge and run rolls.
[*][b]Preacher of the Faith[/b] - Units within 9" of a model with this rule can use the model's leadership stat for morale instead of their own. [/list]
[h3][u]Play Style[/u][/h3]
At a first glance, the Chosen look underwhelming and nearly everything is overpriced; judging by base stats alone you are paying more for less (Enhanced Purifiers cost nearly twice as much as anything in their weight class and Rejected Spawn has a chaff-tier stat line for a battleline infantry cost). However, the Chosen are terrific buff magnets due to a great selection of battle prayers from their War Clerics (who also help stabilize the Reject's otherwise terrible leadership thanks to the Preacher of the Faith special rule), and are a highly customizable army. Rejected in particular partially make up for their terrible stats with their ability to take two gifts instead of one.

Rejected Fanatics with Extra Limbs and Bladed Talons are potent melee blenders while Rejected Spawn with Beastly Bodies and Feral Rage are as fast as cavalry and some vehicles when wounded (don't let the fact that Rejected Penitents and Enhanced Inquisitors can force wounds on other units instead of themselves run by you). Enhanced Church Wardens with Horizon Vision incredible snipers and even light anti-vehicle threats when paired with the Pillar of Light battle prayer, giving them AP to their shots. Enhanced Hierarch Guard with Blessed Flesh are practically an auto-include as their bodyguard aura is invaluable to the Chosen and regeneration from Blessed Flesh means that they can stay alive longer on a 5+, improving to a 4+ with the "Chalice of Purity" item.

Key to your play however (and the main target of the Hierarch Guard's bodyguard ability) are the War Clerics and RADX Relics. War Clerics are already pretty tanky at range but its still wise to keep them protection. One unlucky shot and suddenly your entire frontline of Rejects are having a crisis of faith and running away. RADX Relics however need the protection as while they're carried by Rejected, they can't take and Gifts but are still valuable due to their reroll morale test aura. If you are feeling brave, give them the Leeching Lodestone upgrade and charge them into melee to force mortal wounds on wounds rolls of 6+ (its really fucking funny watching Rejected Spawn suddenly be able to take down a vampire Umbraghiest because of this thing) or for even more memes, take the Radiant Lantern and turn the relic into a really shitty blessed turret that causes anything it hit to have a -1 to hit until the next turn.

Tl;dr - The Chosen are a widely customizable army due to the Creator's Gifts and have a selection of strong supporting units that are sorely needed for their overpriced buff sponges. Pray to the Creator and smite your foes with your mastery of the human body, the God [s]Emperor[/s] Queen Protects!

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Now is when I wished I could write up more stuff for these lol. Other ideas that aren't written include items that add to the Enhanced Regeneration roll and a Rejected war priest-lite called a Rejected Faithful who'd only know one ability that the War Clerics know.