Impregnator Kings is a CYOA that originally started on pregchan back in December 2015.
You are Sir Edward, a medieval (ish) aristocrat who wants to become a King. Unfortunately, Edward is the son of a Duke and marrying into royalty would be marrying above his station. Fortunately, he has a fetish for impregnating women, and the seductive good looks and charm to pull it off. Edward has slept with dozens of women and sired even more children. His reputation for virility and potent sperm allowed him the opportunity to marry into several different royal families, all eager for an heir, as quickly as possible.
That is the basic premise. The actual threads they first appeared in have mostly 404'd, but the internet archive continues to have them. They can still be read and enjoyed here:
Thread #1: https://web.archive.org/web/20170619163636/http://pregchan.com/d/res/12251.html
This spans the beginning of the game when Edward selects his future bride, until Edward reaches Ruhemania and learns there's more to his new country than ever was hinted at.
1. Sir Edward of Virilia: The "you" of the story. He is fair-minded, and gregarious. Fond of outdoor activity and strength. He possesses a charming nature that attracts women to his bed, though some easier than others.
2. The Matchmaker: The young female aristocrat who introduces profiles of all available wives for Edward to choose from. He never learns her name.
3. Varillo: A mercenary who guides Edward through dense swamp and hills to reach Castle Valachia and begin his new life.
4. Ricardo: King Vlad's master of coin. A dismal old man, full of secrets. He appears to be King Vlad's only adviser, and one of the only other aristocrats in the castle.
5. Daniella: King Vlad's personal maid. Her position is independent of the servant hierarchy and subject to no authority but King Vlad himself. He has also given her blanket permission to do anything she likes, anywhere she likes. Tharja insists she isn't a spy, but just a busy-body maid.
6. King Vlad: The undisputed Sovereign of all of Ruhemania. Was originally an Independent Duke who fought a decades-long unification war to unite the various independent aristocrats in the country. Values obedience. The impalement stakes around the castle are a stark testament to how much.
7. Tharja: Edward's matchmade bride. Obsessive, and perhaps a little naive. Devotes herself fully to Edward. Fond of books and reading. The castle library has been claimed by her.
8. Elizabeth: Edward's personal maid who sees to his daily duties. Scatter-brained and prone to mistakes.
1. Slept with and impregnated the matchmaker.
2. Chose Tharja of Ruhemania to be his bride.
3. Help the sailors as you travel.
4. Be obedient to Varillo's mercenary gang as they guide you to the castle.
5. Meet immediately with King Vlad.
6. Be honest with Tharja about your sexual history and reputation.
7. Edward reciprocates Tharja's feelings and they fall mutually in love with each other.
8. Birch Elizabeth honestly.
9. Gain Ricardo's 'friendship' and hear the history of Ruhemania.
Thread #2: https://web.archive.org/web/20170619123902/http://pregchan.com/d/res/14131.html
This spans the third meeting with King Vlad (in which Edward unwittingly antagonizes him) until Tharja reveals her secret to Edward.
1. Margaret: Elizabeth's sister and Edward's nightly duties maid. Calm-headed and professional.
2. The corpse in the oubliette: A mystery hidden in the dungeon.
3. Sully: A female solider who has 'thrown away' her womanhood to join the army.
1. Explore the dungeon and discover the oubliette.
2. Provoke King Vlad's paranoia; receive a horse and stablehand.
3. Take Elizabeth's virginity semi-publicly.
4. Keep your dignity before Daniella and don't beg her to help Elizabeth.
5. Spar Sully in a way to teach her how to fight and drill bad ideas out of her.
6. Attend the castle's religious service.
Thread #3: https://web.archive.org/web/20170619104842/http://pregchan.com/d/res/15553.html
This spans the time Tharja reveals she is a witch until Edward agrees to Beatrice's plan to kill King Vlad, and Edward has a moment of introspection in Daniella's room.
1. Beatrice, the Infinite Golden Witch: A powerful and capricious witch living in isolation.
2. Patchouli, the Witch of Knowledge: The true identity of the matchmaker, who slept with Edward to curse him with sterility.
3. Great Witch-Persecutor King Vlad: A man who started a great war to unify a country as a pretense of purging every last witch from the land. All witch-hunters came to serve him. Little is known about his true motives.
4. Witch-Hunter Daniella: An utterly devoted woman dedicated to the extermination of all witches. Highly skilled in combat and trained to utilize her role as a maid to prepare for the threat of witches.
5. Witch-Hunter Simon: Daniella's husband, serving as a courier. Was killed by Lorenzo (presumably) and thrown into the oubliette long before Edward arrived in Ruhemania.
6. Lorenzo: Tharja's dead older brother. Indirectly caused the entire chain of events that lead to Tharja becoming a witch, and Edward's wife. Attempted to kill King Vlad for magical power and to take his throne.
7. The senior guard: King Vlad's army is disorganized with no designated leadership, but everyone recognizes the senior guard is the one in charge.
8. The head maid: A fat woman who is the head of the servant hierarchy.
1. Collecting a longsword; rope; and a fire-starter for the journey.
2. Attempting diplomacy and maintaining your patience in the face of Beatrice's provocations.
3. Explaining the full situation in the castle to Beatrice.
4. Peacefully persuading Patchouli, Witch of Knowledge, to indirectly remove your curse.
5. Agree to Beatrice's plan. Kill Daniella, throw her in the oubliette, help Beatrice assassinate King Vlad. Become King and revive the legacy of magic in Ruhemania.
Thread #4: http://web.archive.org/web/20160412094726/http://bbw-chan.net/elite/res/536.html
(This comes from a brief period when the story was hosted on bbw-chan, and there's a now defunct link to an ad connected to this link. Just hit refresh and it should go away.)
This spans Beatrice arriving at the castle until Edward takes the first steps to seducing Sully.
1. The Lost Witches of Ruhemania: Witches killed during King Vlad's extermination campaign. Beatrice hoped one of them would still be alive.
2. The peasant leaders: The peasants capable of skilled labor.
1. Keep King Vlad's tower for yourself instead of giving it to Beatrice.
2. Send King Vlad's embalmed body around with an honor guard to be displayed to the people before its entombment.
3. Give the Church a normal donation.
4. Share goose with the peasant leaders.
5. Complete Beatrice's puzzle with a 'neutral' solution, and hear Beatrice's lesson about how trying to please everyone is impossible.
6. Make Beatrice your spymaster and have her spy on the fat maid.
7. Hire an architect to build Beatrice her own tower.
Thread #5: https://web.archive.org/web/20170619134833/http://pregchan.com/d/res/16909.html
This spans Edward finding out Beatrice will eventually expect Edward to provide her with human bodies to experiment with until Beatrice reports on spying on the priest who visits every two weeks.
1. The blacksmith's widowed sister: A common woman who was still a virgin after being widowed, until Edward impregnated her.
2. Erika, Witch of Truth, or Devastation: The only other survivor of King Vlad's extermination campaign. Faked her death and was living in hiding.
3. Malon: The stablehand hired by King Vlad to keep Edward's new horse. Has a body and personality meant for breeding.
4. The architect: a presumably skilled man who will build Edward a fine tower.
5. The power-hungry maid: The fat maid in charge of the servant hierarchy is revealed by Beatrice to be a bully and a tyrant who leads them ineffectually. She likes to be lazy and push her work on to other maids, especially ones she doesn't like.
1. Take Tharja's side over Margaret and eat a biscuit she prepared without having it tasted first.
2. Spar with the soldier fairly while Tharja spectates.
3. Attempt intimacy with Beatrice.
4. Do your best to spare your loyal soldier from Beatrice's wrath after he almost kills her without being too lenient to appease Beatrice.
5. Choose a 'mixed' plan of local labor and imported material to build the tower.
6. Have Beatrice investigate Ricardo.
7. Had Erika escorted to the throne room, then brought Beatrice to meet her.
8. Delayed inviting or denying Erika to the castle and told her to come back in a few months.
8. Told Tharja privately about Erika's role in her family members' deaths.
9. Had sex with Erika, gave her an old abandoned manor with peasant farms in the area. Did not give her a carriage for easy travel.
10. Did not remove the impalement stakes.
11. Encouraged the younger soldiers to shout your name during the Church service, despite the suppression of the older guards.
12. Decided to hold a jousting tournament at the Faire.
13. Have the tower workers live outside the peasant settlement.
14. Investigate the priest during confession.
15. Convince Tharja she must live on as a witch after you perish a mortal's death. Agree not to partake in any activity that could kill you prematurely.
16. Make Elizabeth your slave.
17. Publicly humiliate an older guard in the name of supporting the younger guards.
Thread #6: https://web.archive.org/web/20180307043453/https://pregchan.com/d/res/24119.html
This spans Edward hearing Malon is likely pregnant until Edward takes Margaret aside to discuss Elizabeth.
None in particular.
1. No more spying for Beatrice at the moment. Have Beatrice tutor Tharja in witchcraft.
2. Encourage Tharja to help you impregnate women.
3. Have the maids prepare double the necessary amount of rooms for the Faire.
4. Have Beatrice help discourage Tharja's fear of the Church. Allow her to also teach her about witch-society.
5. Make the jousting tournament anonymous.
8. Choose Father Tomas as future chaplain (who will bring nuns).
9. Almost started an orgy in semi-public in front of Margaret.
10. Eavesdrop on Margaret and Elizabeth's conversation, then try to talk to Margaret directly.
Thread #7: https://web.archive.org/web/20180930122947/https://pregchan.com/d/res/33943.html
This spans Edward's absolute last-minute changes before the Summer Faire to his first meeting with Corrin.
1. The burgmeister: A commoner elected by other commoners to see over the local burg of Kervuva, an important source of resources for the castle.
2. Dimitrie: A nobleman of somewhat stunted capacity for intrigue. Carries a sword. Will participate in the joust.
3. The 'early' merchant: The first merchan to arrive for the Faire, tried to 'win over' Edward's favor.
4. The nomads: Traveling performers who received permission to move their wagon inside the castle.
5. Corrin: A young noble with a gift for eloquent use of words and a fondness of books. Claimed he would not enter the jousting tournament.
1. Ultimately do nothing about Elizabeth other than reassure Margaret you are paying attention to their needs.
2. Decide the prize for the jousting tournament will be a Knighthood.
3. Invite yourself to Kervuva at some time in the future.
4. Recruit loyal guards to watch for suspicious activity to report to you.
5. Respond to Dimitrie's claims by offering to send troops to Torbuja.
6. Maintain strict fairness in the Faire marketplace.
7. Allow the nomads to enter the castle if they swear to follow your laws.
8. Actively recruit women into your army.
Thread #8: https://pregchan.com/d/res/48104.html
This spans the dinner with Corrin's family until Robin tells Edward about the plot against him.
1. Camilla: Corrin's eldest sister. Has a voluptuous figure perfect for babymaking.
2. Cordelia: Corrin's second eldest sister. Has a slender form that would be well filled out by pregnancy.
3. Robin: Corrin's third eldest sister. Rather petite, boyish figure, all told.
1. Invite Corrin and his family to a private dinner with you, Tharja, and Beatrice.
2. Spar Dimitrie yourself… and lose.
3. Force Varillo's gang to give up their machetes to enter the Faire.
4. Personally announce the Faire is open.
5. Hear about the Emerald Knight's attempt at bribery.
6. Take Cordelia's first time and impregnate her.
7. Allow Robin to join your army with the implication she will be able to use her military strategy. Hear about the plot against you, but delay any decisive action, yet.
8. Have sex with and impregnate Robin.