Re:Zero Kara Hajimeru Isekai Seikatsu - Chapter 55Arc 7, - “The Cacophony of the Demon City”

Zhang Gong decides to learn light magic, a magic few show interest in and eventually becomes the legendary Grand Magister. While trying to end the continent’s east and west separation in order to unite all of the different races, he becomes every race’s Child of Light.

[Ding, your frog was afraid of your death, so he went on a trip overnight and stole a shelter for you! 】

…

Reborn into a world of global catastrophe apocalypse.

In the face of global recovery, zombies, fog, meteorites, prehistoric creatures, glaciers, earthquakes, acid rain and other devastating global disasters, the only thing Ye Su has to do is to survive.

Unexpectedly, he got a traveling frog when he arrived. The frog was afraid of Ye Su’s death, so he simply stole a shelter!

Ye Su: “???”

But what’s even more outrageous is yet to come.

[Ding, your frog is afraid that you are not stable enough, so he stole the source of fire for you]

[Ding, your frog was afraid that you would be bitten, so he stole the antiviral potion overnight! 】

[Ding, your frog stole the Zanpakutō for you! Additional Asura – Blade Skill! 】

So, when everyone was avoiding zombies, disasters, despairing for food and water, Ye Su had already carried a big knife, drove a car, and came out for food!

- Description from novelbuddy

The Mc reincarnates in a world of magic and adventure as a Leech, follow his adventure in this mysterious and exciting world as he goes from the weakest creature to the shadow being that everyone is afraid of. Will he pursue the path of strength alone? Or without realizing it he will become the king of the greatest empire that ever lived.

A series of short stories in the world of Toaru Majutsu no Index organized into chapters featuring Kanzaki Kaori as the protagonist, going around the world and space doing missions for the Church of Necessary Evil, however, there is more than meets the eye as each incident is connected.

One chapter was bundled with each limited edition release of the Toaru Kagaku no Railgun anime DVD and BDs, with all of them together being equivalent to a single normal Toaru Majutsu no Index volume