Koko wa Ore ni Makasete Saki ni Ike to Itte kara 10 Nen ga Tattara Densetsu ni Natteita

The Hero’s party was attacked by a large group of powerful devils. The party will no doubt be annihilated if this were to go on. One member of the party, the strongest mage, Rakku, decided to stop the enemies in their tracks. 「Leave it to me here and go!」 「But……」 「Hey, I’ll catch up immediately, alright?」 Rakku mindlessly defeated the enemies, over and over again. Using his special skill, Learning, Rakku learned the demon’s magic. As he studied and utilised the demon’s abilities such as Drain Touch, he continued fighting, without rest nor sleep. The demons got stronger and stronger, but Rakku grew rapidly as well. Rakku battled for 10 years, until no demons came at him. Rakku returned to the capital, and was surprised to discover that his own name had become the currency, and a gigantic statue of him, albeit fairly beautified, was made. Due to him relentlessly absorbing the vitality of the demons, he had become young again. An appearance unfitting of his age. Godly abilities. 「I stand out too much」 Rakku concealed his true identity, and decided to pretend being a novice adventurer by disguising himself as a F-rank warrior despite being an S-rank mage. His adventure in this now peaceful (?) world starts now!