This makes much more sense than MC, just remembering random tidbits from the novel on how to acquire every skill.

The story is called "Dragon's Ascent" so unless you add Devil in front of it, it would be misleading. A lot of authors make their mc join the Rias because that's the easiest way for their mc to join the waiting game with Raiser. I hope you will not fall for the same trap and keep your mc free. If you grab Boosted Gear, Rias' rating game with Raiser won't happen for a few years, so you can take your time with this plot point.

You do remember that mc is a sociopath, right? Every time he shows any emotion to others, he is playing a role to achieve something.

Time to make some impurity cleansing pills(potions) to become beautiful and increase gains fron training. Also, true alchemists don't train, they use potions to train for them. Every time your mc will face a problem in the future, his first thought should be: "Can I make a potion for that?". He should also think about crating mutagens of some kind, especially if he wants to stay human he would need to evolve.

The reason to take production makes sense, I just hope this mc will not be complaining about how weak he is all the time, like your other dxd mc.

I ship it

I noticed this before, but MC has too many things regarding weapons when 1 would have been enough. He has 5 in 1 weapon from his dad, which should have been enough even if it is a bit too op for a starter weapon. Then he started learning how to forge, which sounds alright if he wants to upgrade his main weapon, but it was made by the best smiths in the underworld, so it would be hard to get to their level. Projection magic is next, he only really needs it to produce arrows, which could have been solved by some magical quvier that duplicates any arrow inside it. And now he gets flames that can become weapons, I know that they have more abilities, but right now, it's really useless as he can use projection to do the same and use shadows in place of constructs. MC has way too many powers that do similar things and he doesn't have time to master any of them and despite that he is already way too strong for his age. You had to nerf his shadows already because you have seen that they are too op but you decided to keep on giving him more powers. Blocking some of his powers just so you can have him in a dangerous situation is not a solution, and you already have to do this when he is 7 years old, I have no idea what you will do when he is 14 and way stronger than now.

I was wondering what will happen with Sybile in the future as she was clearly not powerful enough to follow mc on his multiversal journey. I know that relationships are not only about how strong you are but being carried all the time by your way stronger partner seems really demeaning. I enjoyed their chemistry but could never see her as more than a current fling. Would have preferred for her to survive, but it's still nice to give mc some character development as he clearly became a bit too sure of himself.

I like the relationship with Sybil, but I hope she will start working harder on her magic because soon, she won't be able to measure to Raylin and become damsel in distress in future fights.

Why did you make 1 page chapter rather than include it in the last one?

Lily has lived in the magical world for 20 years and still doesn't know the basic stuff about contracts? Also, her angry reactions are a bit immature, I could see teenager Hermione reacting like that, not a mother of 3 children in her thirties.

That is the best Dumbledor ever. Any other fanfic can't compare xD

The fact that this is the first male character here other than mc seems a bit strange...

Did you mean 'pun'ful?

In that case, it should be -99%. Anything more than 100% is going into the negatives.

Does this mean he loses 100x of his hp regen value per second? If not then 100% would make more sense.

Is this foreshadowing for Adam getting demon/hollow powers due to experiments in the future?

She didn't go "Ban...KAI". Weak...

If you don't say KAI with all your might, you are not doing bankai right :)