"Eromanga Sensei" volume 4 by Fushimi Tsukasa. This volume deals with the annoyances of meeting your archenemy. It's also where characters learn that "eromanga" most likely came from the usual "ero manga" everyone suspected all along.
The dark character in the cover background is a competing illustrator who made an ominous appearance at the end of the previous volume. For a series that has been adding new characters every volume, readers should expect some of them to turn bad or redundant by now, but this is not the one. This new character made a bad first impression in her attempt to challenge Sagiri and take over the title of "Eromanga Sensei", but immediately got better this dialog:
"This is the original Eromanga Sensei's ultimate skill... Eromanga Flash!"
"... what did you say? ... I didn't catch the name of that ultimate skill, can you repeat again?"
"Eh? Um... that's... you know... eromanga flash."
"What?"
"... ero... flash..."
This turned out to be a relative positive character in the end, and readers gained a bit more about Eromanga Sensei's history in the process. It follows the same formula of enemies becoming friends after a battle, just like Masamune versus Elf in volume 1 and Masamune versus Muramasa in volume 2. Except the battle in this volume has the exact elements that I would find annoying if I had a real life archenemy: someone who does exactly what you do, but worse, all while getting more credit. It will take a bit more time to really like this character.
Other than new character developments, I was happy to see the returning characters, especially with Muramasa speaking on behalf of all light novel fans when translating the original novel a comic: "don't you dare cut out anything" and "I will kill you if it's boring". These meta bits are really precious.
Looking forward to Sagiri opening up to the outside world in volume 5.
Previous (2016-01-04): "Eromanga Sensei" volume 3 by Fushimi Tsukasa
Next (2016-01-18): "Tesagure! Bukatsumono"