Köinzell is a master swordsman who, along with thirteen other heroes, was sent by the Szaalenden Empire to block an invasion of their enemy Wischtech. Along the way three died, four betrayed the others and seven defeated the traitors and returned as heroes. At least, that's what people believe. In reality the ‘Seven Heroes' were the real traitors, defeating the four true champions after the seven had fled the battle in cowardice. Köinzell has bided his time for twenty years, honing his skills and recovering from the brink of death so that he may avenge his fallen comrades. The time for vengeance has finally come and all who stand in his way shall be dismembered without hesitation, but it won't be easy as everyone believes the lies of the traitors. With all the soldiers in the land and the public against them, Köinzell and his ragtag allies may have to sacrifice everything if they are to prevail against the might of the entire nation.
This is mostly a gut feel recommendation. Sure both manga are action adventure series and in both there is a plot revolving around 7 heroes, but just that in case of those two series would not be enough. Nonetheless something tells me that fans of one of those manga could like the other one as well.
P.S. A word of warning: Ubel Blatt has some mature themes going on. At leas they get greatly reduced after the first few volumes.
For some reason I thought of Maoyuu Maou Yuusha while reading Ubel Blatt. I had an impression that Maoyuu Maou Yuusha could be considered a light version of Ubel Blatt. So if you tried reading Ubel Blatt and the only thing preventing you from enjoying it was the explicit content, then you probably could enjoy reading Maoyuu Maou Yuusha. I forgot to mention, but both of those are medieval-like fantasy series and the art style is somewhat similar.
Both stories center on betrayal. While rebirth concentrates on revenge for lost love, Ubel Blatt concentrates on patriatism and lost comrades.
Both Ubel Blatt and Superior are medievalish, fantasy action adventure series. Uble Blatt has larger quantity of explicit content compared to Superior (though it's still not as bad as it may seem at first), on the other hand Superior has a romantic subplot which Ubel Blatt seems to lack. Nonetheless, if you liked one of those two series, you might like the other one too.
A powerful hero of the past returns and his\her actions are bound to shake the world. How can he\she not shake the world, when his\her intentions seem to be bad. If that sounds interesting to you then you're best bet would be to go read Ubel Blatt and\or The Legend of Maian. Additionally, both of those are medieval-like, fantasy, action-adventure series.
P.S. Keep in mind that Ubel Blatt has some mature content in it (though it gets watered down after one or two volumes).