Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 15 - 15-42. Mastermind

Long Fei, a cross-timer and doujin, is an otaku who traveled to another world. In the original world, he was an otaku fan of Gundam and military science fiction.

He died in an accident and was reincarnated into another world. The Gundam works he had read before his death and the techniques in various military novels could be brought to another world.

How would he use the Gundam that Long Fei created? What waves can be caused in this different world?

- Description from novelbuddy

In the business world, legend has it that he’s cold-blooded and ruthless. Yet at home, he dotes on his beloved wife to the bones.

‘Why am I married to this demon?’ After accidentally provoking a certain demon, she becomes his possession. From then on, she is forced into a shameless, wanton life…

“Mr. Pei, is there anything that you’re dissatisfied with Mrs. Pei about?” a reporter asks.

Mr. Pei’s dark eyes narrows. ‘The only thing I’m not satisfied with…’

Mr. Pei answers brazenly, “Lasting for only five minutes after charging for two hours.”

Mrs. Pei’s cheeks instantly turn red and she curses inwardly, ‘This darn perv!’

The reporter asks again, “What about you, Mrs. Pei?”

Gritting her teeth, Mrs Pei replies, “Lasting for two hours after charging for only five minutes!”

That night, Mr. Pei smiles wickedly after lasting four hours. “Are you satisfied now?”

Nagasawa crossed to Naruto Universe and was bound to Konohagakure.If Konoha is severely damaged and destroyed, Nagasawa’s lifespan will be reduced.He panicked at the thought of the upcoming Nine-Tailed Demon Fox's attack , and the thought of Konoha getting destroyed left him in despair.Fortunately, while bound to Konoha, he can obtain templates of powerful characters.At the beginning, He got the Whitebeard template! Since it's the Whitebeard from the Summit War of Marineford, he can use Tremor-Tremor Fruit's ability and Haki.Facing the Tailed Beast Ball, which terrorized Konoha Shinobi, Nagasawa leaped and shattered the Tailed Beast Ball with one punch!