The devil daddy

Killing your patron is a task very few warlocks pursue fearing wraith of the patron could do but what if the patron had a soft spot for you? this is the unexpected situation that Alistor finds him self in his Devilish father who is oddly sympathetic to his kin. When his son was born a true cambion his mother died in birth Alistorius named his son and lead him to foster parents who he mind he altered the memory of replacing there son with his own and storing away his fiendish side so he would be a true human. after which he then waited to create a pact with his son so that he would not be feeble and weak in the cruel mortal plane. soon after he went to fight in the blood war, he added a secret script passing over his unholy power to his son in the case of his death expecting to never return from the Blood war instead of the honorable demise he wanted he survived 20 years before being promoted out of the war and officially retired by Zariel bit there is Speculation by some that Dispater requested his removal from the war for easier spying appon him, and so it was Alistorius left the war a veteran with high possession under Zariel's close command currently under the command of "stay alive catch stragglers that get past the front line and in the case of a mass break through call for me and survive".
Alistorius is a power full Arch devil with great magical and physical power his spell save DC is 23 (8+5+10) his strength is a 26 and he is a expert in deception and persuasion. his speed is impressive and his spell versatility is too casting any warlock spell as many times as he wishes bellow 6th level.
Alistor's Trial;
in stead of a straight up fight its gonna be a few individual battles.
Yugaloth- accepts you as his warlock and sees you a fight
12 imps- you can deal With a crowed but you have only dealt with Demons so far
Warlock (2 imps supporting)- you have bested my Warlock so I Know you can fight against magic but can you fight without it
4 Flail snails- well without your magic you did well only a few steps from being worthy enough to challenge me head on. convince the noble of silver wood to kill his own son then you will be able to challenge me, now begin Casts banishment (level 9 DC 23 charisma save)
Quest - Laughs Hysterically I can't believe he did it to Asmodias I swear funniest shit I've ever seen in 3 centuries, ok lets brawl. throws down his sword and raises his fists. Fight. (refuses to cast spells excluding cantrips and use any weapons) as the fight begins he transforms himself into a Horned devil like creature but with long claws instead of weapons, his hurl flame uses his charisma (30 so +5) but his proficiency is lowered to +3 instead of +5 as he is not quite used to his body making the attack +8 instead of +7 and +5 is added to the damage, his strength is also lowered to that of a horned devil in this form so the attacks become +9 instead of +10 damage stays the same but DC's become 18

Themes

Deception and a game of whit intelligence and charisma leading to a physical battle. 
A twisted kind of love, the inner battler of Alistorius his outer devil with his inner human.

Structure

Exposition

heading into the even the top of hell is a journey to say the least risk of two pure evil forces pushing against one another and over you is a fear worth having. exploring hell will lead to many devils who simply wish to get what ever they can out of you but in this hostile area there is a Yugaloth that offers you protection surprisingly for free (this applies to Alistors ONLY the others will have to pay minimum 100gp but in classic yugaloth fashion they switch side depending on who is paying more, genral rule for value of a soul;* is worth about 1000gp per CR or 2000gp per level* this should guide how much a devil will pay to pay of the yugaloth ,Alistors current tab is 4 million gp payed by Alistorius). the yugaloth knows little of why he is being paid to protect them but cares not for chatter.

Conflict

Zarial and Dispatchers spies show up and under the order of Zarial a imp was asked to contact them and ask a few simple questions, Who are these people, why is this yugaloth protecting these mortals, who is paying for the services and what are they doing in hell and how did they get here. Zarial is willing to pay the fair price for these souls ask's the Yugaloth how much for each of them as well as asking the players weather they would consider giving up there souls or fighting in the blood war in there current form and how much they would have to pay them. if conversation doesn't work out then they could expect a few visitors to take them by force. Through out this Dispatchers spies watch in silence curious of what might happen.

Rising Action

after being attacked by Zariels zealots the yugaloth decided that this area is unsafe and is going to guide them to some one safer and stronger this is Alistorius who sits waiting for something any thing to happen. seeing his son brought to him by the yugaloth acts as if he doesn't recognize them although he had been watching in his spare time. Alistorius continues to act non wiser until he tires of the conversation and orders the yugaloth to defeat Alistor for him, the yugaloth accepts and combat commences (This is Alistorius's attempt to test his streangth and growth) if he defeats the yugaloth he is considered a worthy challenger and hence feels free to recognize him as his patron but he is still far to weak to fight Alistorius himself, he then demands a task of Alistor "as my patron do-er of my word i command a simple task of someone of your power take over a city hell even a town head back to the mortal plain find a settlement and ensure the people of that town neel before you then I shall grant you some more respect" allow for further conversation, he then snaps sending every one back to the mortal plane on a failed DC 25 charisma save on being successfully resisting his spell he moves on to the next step "maybe you are strong enough to face me seems to me you're more then any mortal" letting out a brief chuckle "say the word and we spar don't worry i won't kill you, you still have a world to conquer." then on forward he is free to challenge his patron to battle whenever he is free.

Climax

The fight should be long-ish lets make his fighting form low damage high health (Note this is not his full power) after losing he will be dashed back to the mortal plane to grow in strength or complete his task if not yet completed, if he gets below 200 HP then Alistorius believes he is strong enough to rule the world and activates a magic circle to protect himself for his speech. "it seems you have grown a lot from when you where younger I'm glad, I always thought my self a fool that my lineage could be mortal I offer you this " he extends his hand and a violent red flame bursts out of his hand "This is the Devil in you I took away from you as a child accept it and you will become a true cambion a fiend of hell but free from its chains" on accepting the the fire he decided that his time is now "now I am ready to pass my power on to you..." raising his sword this is when Zareal and Dispatchers spies intervene but they can't pass through the magic circle Alistorius "Fucking imps what did they think they could do against me." and in that moment a Holy radiance falls down around him and Zarial stands before him "This is how you treat Devil kind you foolish fool you'll die before you can give him any thing" Zarerals blade pieces his chest before he has a chance to do it himself bleeding he seems to write something on a piece of paper in his own blood as he speaks once more "its too late all that was left was for me to die who is the fool now" then extends his hand to the party once again DC 25 saving throw or be sent to the Mortal plane. on returning the the mortal plane a piece of parchment appears in Alistors hand written in blood it reads "my power is yours, Rule the world". Zarial proceeds in stabbing him as they leave "how dare you try to give your power away to a fool like him you'll die a thousand time for disrespecting me.".

Falling Action

With Alistor's power his own and Alistorius dead Zareal back busy with war, the party is left with a half devil team mate and a fun adventure and a target on there back whenever there in hell as Zareal stuck a sizable 15 000 gp bounty on the whole party. now he has a ever lasting quest rule the world.

Relations

Allies

Alistorius want's for Alistor to take over the world he see's Alistor as his rebirth and his break away from hell Alistor has the freedom of a human but the intelligence, charisma and morals of a Devil. Alistorius is tired of immortal life and wants to pass on his power but will only do so once he believes his son is strong enough to rule over the mortal world

Neutrals/Bystanders

Dispater, The quiet watcher ,and holder of secrets. Dispater just wishes to watch this whole thing go down and gain from it if he can Alistorius is a well respected devil and Dispater has a strong piece of black mail against him. it also frustrates Dispater that he doesn't under stand Alistorius's plan as it doesn't apply to a devils logic so he watches silently with imp spies and yugaloths who pose as mercenaries for demons. Dispater could push the party in the right direction if its needed as this could lead to him learning more about the secrets Alistorius holds, that said he won't reveal himself easily and wouldn't know the party members or there intentions.

Adversaries

Zerial, They see the Hero in Alistorius and want him where he is, on the battle field of hell. Zerial will do what she must to keep him alive but is a very very busy person dealing with the demon hoard and all so has only lesser devils to send on trivial tasks like hunting some humans running around in Hell. although if it seams that Alistorius is going to die or give up his power she will intervein with a greater devil or yugaloth. She doesn't have much in the way of spies but mortals in hell draw attention and if she where to find out there motives would attempt to stop them or if where to discover there interest in one of her warriors she would leave a spy or two to watch over them.