When I tried to strengthen [the rusty sword], I transformed it into a ridiculous demon sword. Kadokawa Dwango Books

※Please note that product information is not in full comprehensive meaning because of the machine translation.
Japanese title: ライトノベルその他サイズ 【さびついた剣】を試しに強化してみたら、とんでもない魔剣に化けました カドカワBOOKS
Out of stock
Item number: 2M12723
Released date: 09 Jul 2021
Maker: KADOKAWA
An illustration: 赤井てら

Product description ※Please note that product information is not in full comprehensive meaning because of the machine translation.

It's A FANTASY THAT STARTS WITH THE WEAKEST FAILURE WEAPON! THE LAST WEAPON I ADMIRED FOR BEING A HERO, WAS THE "RUSTED SWORD" OF THE LOWEST RANK. BUT ONE DAY, THE TATTERED SWORD WILL WAKE UP? THE BOY WILL RUN UP THE ROAD TO BE A HERO, USING THE MOST POWERFUL WEAPON WITH HANDLING LIMITS!