After ONS: Trapped by the Cunning Professor - Chapter 462 - 463: Two Giant Light Bulbs

The most precious things in the world are priceless. Ordinary men tend to turn a blind eye to this fact. Apart from the treasured air, sunlight, and familial love, there is still one more thing that’s extremely valuable. It’s right beside you and can be easily obtained.

- Description from Novelupdates

Arriving in a fantasy Otherworld, Gauss obtains an Adventurer's Handbook that grows stronger the more monsters he slays and collects. Gauss originally thought he was embarking on a classic adventure to defeat the Giant Dragon, kill the Devil, and save the kingdom. Yet, seeing goblins breeding like pests and multiplying endlessly, along with the fast-growing kill count and rewards in the Monster Atlas, his face grows increasingly helpless...“You have slain 1000 goblins! Intelligence +1, Strength +1, Constitution +1.”“The title 'Goblin Slayer' has upgraded to 'Goblin Expert'. You are an expert on goblins; few know better than you how to kill them.”“...”“The title 'Goblin Expert' has upgraded to 'Goblin Star Destruction'.”

An 18-year-old girl who lost her family in an accident, Yamano Mitsuha falls off a cliff one day and transferred to a different world with a civilization level of medieval Europe. Mitsuha who discovered it was possible to go and return to Earth after a deadly fight with wolves decided to live in both worlds.

「For the sake of security in old age, I will aim for 80,000 gold coins!」

I will try not to let strange things circulate and distort the progress of the world, but I won’t hold back for the sake of my easy life and safety! While carrying three handguns along with words and deeds that appear decent, in her head, Yamano Mitsuha is a sly girl.

Making an effort to make money even with a small body that looks like a child to foreigners!

Oh, my secrets are too dangerous, you said? It’s fine, it’s fine! I’ll transfer away when push comes to shove!

Once through the pirates, Lu En became the son of Monkey d Dragon, a grandfather named Monkey d Karp, and an unreliable and neurotic younger brother named Luffy.

Fortunately, the ghost back system is activated!

The completion of the ghost back is 10%, and the training effect is increased by 100 times!

The completion of the ghost back is 20%, and the training effect is increased by 1000 times!

…

One day, Lu En, a ghost-backed master, appeared in front of Luffy who was shouting to go to sea, and made Luffy cry on the spot.

Luffy: “The pirates in the sea are all monsters like my brother? I don’t want to go out to sea!”

Garp: “For a long time, the two boys, Long and Luffy, with small arms and calves, I really doubt that they are not my sons and grandsons. Like Lu En, they are the grandsons of the old man!”

Warring States: “The strongest creature in the sea, land and air is Kaido? No, it’s Lu En!”

- Description from novelbuddy