Tensei Colosseum

 Over past few years, Fantasy Isekai or Tensei manga are quite bountiful. Most of them are relatively forgettable utilizing R18 fanservice as a bait. But from time to time there are handful that are actually good like this Tensei Colosseum.

Just like many Isekai Manga, Tensei colosseum had a protagonist from a modern life setting transported into Fantasy world. Instead of getting the typical Hero welcome, deemed worthless by the summoner, the main protagonist instead are sent to fight in Colosseum against fighters where the winner had their way with the loser's body just like many R18 Visual Novel. Sharing the look of  Devil Survivor 2/ Persona 3 protagonist, the main character is an Avid gamer who surprisingly not a betamax guy. Only possessing copycat skill and gifted with his Video Game knowledge, the main protagonist surprisingly thrived in the colosseum, defeating several beautiful female fighters who kept falling for him after he had his way with them.

For a R18 Fantasy Manga, Isekai Colosseum is surprisingly a very good Battle manga for its type. So any Shuumatsu no Valkyrie fan would easily take a liking with this one because the battle parts is done pretty well and the story is interesting enough. It appears that Isekai Colosseum mangaka had extensive experience in Doujin scene before he made this series because you won't get a Quality R18 fantasy battle mangaka before gaining some extensive experience. To be frank Isekai Colosseum content is decent enough that it can survive without relying on the R18 contents. However the mangaka is just that generous to let the reader enjoy some good fanservice while looking at what Isekai Colosseum could offer. If anyone interested to look further into this genre, you can look at Toushin Toshi which had similar setups with this manga especially on the latter part.