Do you draw larger than the final and then shrink it?  That will help your line-art look cleaner.  It's something essential if you're going to work with nibs.

Work on your hands.  Think about putting a white outline around him if he's standing on a black background.  Consistency.

The text--not only should you use a better font, but you need to make sure there is about a letter width between your text and your balloon, it could also be half to a third the size and still be readable.  Put the text down first, get the spacing all nice and neat, then draw your bubble around/behind it.

As for Sebastian the character...  He's interesting to me because he poses a opportunity for conflict.  Basically, he's a self absorbed spoiled ass, and whoever this chick he's looking for is, she needs to shun him...  Thus presenting an opportunity for him to change.

But that's just me.

I was really confused on page 4, i think i get it he uses a wormhole to flip the car.. maybe a pulled out shot of him standing on the overturned car would have helped?

overall quality is pretty good, but the fonts are really distracting and don't compliment the style, try BLAMBOT im sure youve been told already. the free ones can be found, and it looks WAYYY better. you've got some good details going on in bgs and such.  but again on page 4 it kind of breaks down when you get into the power use more, so just practice drawing how his power would work in different scenarios.
overall, pretty good job, the character is interesting.

I know this continues from your intro pages but it may have helped to give a little more introduction since you've never done a fight and it's been quite a while since you've gotten Sebastian in so it would have helped refresh the readers on who this guy is. I have to echo what others have said about the consistency here. How are you scanning your stuff? Are you converting it to grayscale before you resize the image? Because at the moment some of your lineart is looking pretty pixely. While the last image is great, I would be totally fine with you doing less detailed stuff for the rest of your art, just try to give your backgrounds a little more love.

God. HIS POWER IS CRAZY.
Your style sometime remind me of Jojo's Bizarre Adventure, especially the page 3 and 4. I think you could make this comic a lot more understandable if you didn't use so thick lines to represent speed, it's kinda off... But I'm sure you'll improve a lot on VOID.
Be careful with anatomy and hands, especially in the two first pages.

Anyway, I want to see more from you. Page 3 was precious.

I suggest using a brush next time, quill ain't giving your comics much love in the end and a brush can give you the same type of tightness a technical pen can give ya with the added bonus of being able to vary line widths with ease.

amazindavid makes a good point, the first drawing on the first page definetly reminds me of Ronin...
Which is alot cooler than the last page which looks very... regular like new DC.

This felt like two different artists completely...the first 4 pages kind of have this late 80's - mid 90's frank miller esque (who stole all his shit from Steranko) look ala Ronin or DK....really blocky and scribbly....and I dig that I dont think it needs to be cleaned up if anything I think you need to add more anomalous lines and doodads...the BGs felt a bit blank so did the characters....details details details...but not cluttery details details that support the environment....well then...we get to the last page that everybody is mentioning and its like BAM different artist...and I don't like this guy...he's not as good as the first 4 pages guy...yeah he can cross hatch his ass off...but who cares...the first guy has more potential and is more interesting to look at than crosshatchy guy...

Id say if your going to mix up styles (the way they do in BD and most Manga) I'd choose two styles that compliment each other....I'd also say if your going to try to refine one of these styles choose the first one..that one kicks the much bootaaay

I guess what anthill said makes a whole lot of sense.  I think I felt that the last page was out of place because it did not share consistency with the other pages.  But to be fair I have seen this sort of thing before in other comics where a break in consistency is used to highlight a dramatic moment but I think the rest of the comic needs to be of a higher quality for this to work.  Not demeaning you or anything, I still think its good it just needs some cleaning.

My bad
I dont mean to offend but i didnt mean to give that good of a score
I score generous but not that much,
So this has pretty good art but looks a bit to rushed there are definetly some points that with a little more work would of looked fantastic. In all it was a good start

Somebody voted a bit too generously for this comic. It's a decent comic, but it's not something I'd give all 10's to.

Anywho, despite my rather negative outline above, the comic is good, but I can see lots of things that really need more work on, for one thing, if you're gonna cross hatch like what you did in the last page, then do that with every page. Consistency is one of the key things to learn when making comics, you can't color a few pages, leave a few of them toned, and color tone in a single comic (I know you didn't do this but I'm trying to make a point here). That makes a comic look rushed and unfinished.

The inking here looked very shaky to me and it was very inconsistent, I did like the last page but I'm left wondering why the other pages didn't look as good. Your backgrounds could use some love from rulers as well my friend. The story here is pretty nice, but there's not really a whole lot to it to really draw me in. I am interested in seeing what happens next, but work on tightening up your inks and keep things consistent.

This is good you've got some good crosshatching skills there especially on faces and such.  I find the last page has too much negative space.  I dunno, it looks good and seems like it was meant to stand alone which is good in certain situations and yet...I find it a little lacking.  I don't know if it necessarily needs a background but that's just me.  Your details are great though and I think you will become better over time because frankly I'm not sure what to point out.  It's a good demonstration though of your character's personality and powers.