The National Sweetheart Livestreamer Is A Pro! - Chapter 21 - You don't have to worry Fi-god, I will guide him well and help him to fulfill his dream.

The contract says she can’t share his bed, but nothing stops him from getting into hers…Rain Clayton’s life takes an unexpected turn when she discovers she’s suddenly married to a billionaire named Alexander Lancaster, a powerful and dangerously captivating man who wants their marriage over before it even begins...Raised by a family that never cared for her and desperate to avoid a twisted arranged marriage, Rain seizes this unexpected twist of fate. Her new husband might be a cold-hearted billionaire, but he's her only escape. Yet Alexander demands a swift divorce.Refusing to lose her one chance at freedom, Rain strikes a risky bargain to keep their marriage alive, even if it means playing by Alexander’s rules. She just has to convince him to want her around… FOREVER.Weeks into their unexpected arrangement, Rain begins to see through Alexander’s icy exterior. But one night, she’s taken by surprise.“What are you doing?” Rain burst out, eyes wide as Alexander casually slid into her bed.“Performing husbandly duties,” he smirked.“You can’t stay here! It’s against the contract!”“I’m not breaking it,” Alexander said with a shrug. “The contract specifies that you’ll fulfill all wifely duties, excluding sharing my bed. It doesn’t say anything about me not performing husbandly duties, including sharing your bed.”The situation had shifted, and it seemed like she was no longer the only one in control...[Warning: r18+/strong mature & sexual content]

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

An ordinary student, a wretched peeper, a cowardly teenager with a kind heart. In a terrorist attack, he inherited the knowledge of countless elites, embarked on a path of God Jagged Tu…

He is an artist!

He is a mathematician!

He is a psychology Doctor!

He is a master of fighting!

In fact, he is a man

Taken off raw site:

A wretched, dirty young man is working during the summer when he was caught up in a mysterious explosion. After that explosion, the young man is then left with the memories and knowledge of dozens of the world’s experts.

He has changed, his heart has become cold, iron-blooded. He became a killing machine, his mind turned mechanical, calculative. Everything goes according to his plans and calculations!

In this magical, slaughterous world, a door is opened for him…

- Description from Novelupdates

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?