No Prep Time
Setting DBZ HELL
None of them are human so Alucard goes schrodinger and can't die.
Now between Father and Aizen it's a matter of if Father can deconstruct the Hogyoku, otherwise Aizen keeps reviving and becoming constantly stronger, considering that transmuting Aizen won't work when the Hogyoku would undo it. Father needs to be able to do something to the Hogyoku or he lacks the means to kill him.
Aizen could wittle down Father's philosopher's stone energy considering that Edward and co did it with conventional weapons pretty easily. Since Father has no concrete way of killing him or Alucard it really comes down to a draw between Alucard and Aizen and a dead Father in the middle.
Essentially, the battle comes to a draw between Aizen and Alucard since both lack the means to off one another with the former's immortality and the latter gaining Schrodinger's abilities. Father will pretty much have his souls whittled down by the two until he gets offed.
@CerusSerenade: how about getting sealed by kido? aizen can create hados that disrupt the flow of space and time and whats the best mindcontrolling resist alucard has done?
Schrodinger's powers allow him to exist anywhere he believes he exists. Schordinger himself was able to enter other people's minds to deliver a message this way, and even after Schrodinger had a shotgun inserted into his head and had it blown up he was back in a few moments to say "sup." Kido isn't stopping him.
As for mind control, Alucard has put individuals under his complete control where they would act and think just as he had instructed them to. Not that it matters, Aizen has no mind controlling abilities to speak of.
Aizen is a fucking troll. Aizen has Kyōka Suigetsu which controls all five senses. Vampires sense are heightened, which would make this Alucard's disadvantage.
Aizen can't be harmed by shit like bullets unless they are reishi and are at his level.
Alucard does not have Reishi and there for it is unlikely that he can even stand in his presence even if the bastard is omnipresence.
Aizen would speed blitz Alucard easily.
Aizen speed blitz ichigo in bankai.
Aizen is way smarter and a better tactician.
With Kyōka Suigetsu, Aizen can make Alucard reject his own existence.
Aizen isn't bound by the reality of humans so Alucards ability there is useless.
Level 0 Vlad Tepes is a bad idea since he his using all of his lives as a means for an army.
Aizen can create countless level ninety kidos, and those mountian exploding ceros that he threw at Ichigo.
Aizen can't be killed period.
Then there is the face that Aizen can do all those Overpowered Kido spells.
Holy bullets or regen-negating bullets don't work either.
You say alucard has to accept his death right?
Well if aizen can controll him can't he make him see himself losing in which case he will eventually break and believes he has lost? I mean aizen doesn't even have to really fight so much as make them see it, feel it, hear it and in extreme cases taste and smell it.
@TheNeutralOne: Aizen can create illusion, not control the body direclty, Alucard will refuse to die to someone who isn't human in character. Hence the eternal stalemate.
@LHWKnight: As I said, Schrodinger Alucard is his strongest form where he cannot unless he accepts and wants to die. Countless Kido does shit, smarts do nothing, KS does nothing for the reasons explained above.
People, PLEASE stop making KS more than it is, it creates nigh-impossible to detect illusions, it doesn't do mind control.
An omnipresent Alucard would likely outlast Aizen.
A stabilized Father still has terrible durability, and will have immense difficulty handling Alucard' speed, plus his defenses will be quickly worn down. Alucard can rip to shreds one by one proven he has sufficient stamina, interest, and bloodlust.