Magical★Explorer

After dying and waking up inside the world of a famous erotic dating sim called Magical Explorer, Kousuke Takioto realizes he's not the protagonist. He's the best friend side character — the guy who exists to make the main hero look good and occasionally get dumped on by the plot. Most people would panic, but Kousuke has one major advantage: he's played this game inside and out, knows every storyline, every hidden mechanic, and every way the world works. So instead of accepting his role as background decoration, he enrolls at the Sorcerer's Academy and starts grinding his way through the magic system on his own terms. His weapon of choice is an enchanted scarf, which is honestly a pretty strange flex, but it works. The magic system here actually has some thought behind it — mana consumption matters, fights have strategic weight, and Kousuke has to be clever rather than just overpowered. Along the way he picks up allies like Nanami, a mischievous maid-knight, and gets mentored by the academy's principal, who also happens to be a relative. The vibe is comedic and light with harem and ecchi elements woven in, but there's genuine fun in watching someone exploit game knowledge in a fantasy setting. If you liked Welcome to Japan, Ms. Elf for its isekai-meets-daily-life charm, or Magic User's Club for its playful take on magic academies, this one fits that same groove. Based on a light novel, so expect the world-building to have layers.