Despite what you might think from seeing all the 10/10 comments, this manga is actually not all that good. It looks exactly like Berserk, but with downgraded art, story, and character designs (a half-elf? seriously?). I don't understand why this manga is so popular on Manga-Updates. I really hope it gets better.
This is an addition to my original comment, responding to the people complaining that the series should not be compared to Berserk:
I do not compare every fantasy series to Berserk; you're welcome to browse my public lists to view my comments on various series. The fact is that UB has a lot more in common than just being a fantasy series.
Both are gothic action-horror stories. Both are set in fictional countries modeled after Europe during the Dark and early Middle Ages. Both draw elements from German folklore. Both stories follow wandering, lone-wolf, powerful swordsmen on quests for revenge against comrades that betrayed them. Both feature the main character killing evil feudal lords who are able to transform into a 'true', more powerful form within the first couple volumes. Both contain explicit violence and sexual scenes. Both have art styles that emphasize grotesque features in most of the non-main characters. Guts starts Berserk as the "Black Swordsman"; Koinzell starts Ubel Blat as the "black sword". Guts has a scar across his right eye; Koinzell has a scar across his left. Guts has a metal arm; Koinzell wears large metal gauntlets.
A couple similarities might be a coincidence; this many is a pattern.
I will concede one thing: the first volumes of Berserk were not all that great either. It's possible that Ubel Blatt may get much better. However, based on what has been scanlated so far, it is not very good, and certainly not worthy all the 9s and 10s it has received, especially when it seems so derivative of Berserk.