Oricon (Japanese research organization) released its weekly Light Novel ranking for the week of Dec 19 2025.
※The English titles of works may not always be accurate as some have not been released overseas. Thank you for your understanding.

Related rankings are compiled here
Oricon Comic Ranking Summary

3rd place: Kirby and the Great Underground Adventure!

Kirby embarks on a grand adventure deep underground!

King Dedede kicks off the "Mega Ton Punch Contest," where the strongest fist in Dream Land is decided by smashing rocks barehanded. But things go too far when Dedede accidentally punches open a massive hole—and falls right into it!

To save him, Kirby, Bandana Waddle Dee, and the ever-knowledgeable Wise Waddle Dee set off into the unknown depths of the earth. Meanwhile, Meta Knight also heads underground alone, driven by a secret mission…

A thrilling adventure begins as they face powerful enemies lurking in the underground world!

2nd place: Death March to the Parallel World Rhapsody 34

To find Karina’s missing mother, the group sets off for the faraway continent of the Ancient Dragons!

After resolving the Heaven’s Wrath incident, Satou and company return to the capital only to learn that Karina has gone off in search of her mother—last seen heading toward the Ancient Dragon Continent. Realizing the airship she's on is low on fuel, Satou rushes after her, only to find their ship crash-landed on a deserted island.

As they wait for repairs, the party enjoys a tropical beach break, but soon reach their true destination. However, Karina's mother is apparently located in a forbidden, men-only royal harem—!?

A heartwarming isekai sightseeing adventure continues in Volume 34, as the party reunites and searches for a missing loved one!

1st place: That Time I Got Reincarnated as a Slime 23

With Rimuru’s return, the forces of Tempest are filled with renewed determination.

In the midst of this, Rimuru receives shocking news from Velzard—
information that could fundamentally overturn the nature of the entire conflict.

Meanwhile, Ivarage begins to make troubling moves of his own, plunging the situation further into chaos.

A true all-out war.
As everyone is pushed to their limits, the fate of all rests upon a single slime.

The immensely popular reincarnation fantasy finally reaches its main-story conclusion!

Related rankings are compiled here
Oricon Comic Ranking Summary

Ranking / Estimated number of copies sold / Estimated cumulative sales volume / Title / Author

1 11,526 98,049 That Time I Got Reincarnated as a Slime 23 (Author) Fuse / (Illustration) Mitsuba?
2 10,074 10,074 Death March to the Parallel World Rhapsody 34 (Author) Hiro Ainana / (Cover Illustration) shri / (Front & Interior Illustration) Megumi Nagahama
3 7,651 7,651 Kirby and the Great Underground Adventure! Mie Takase (Story) / TOW and Poto (Art)
4 7,502 7,502 New Testament: A Certain Magical Index 14 (Author) Kazuma Kamachi / (Illustration) Kiyotaka Haimura
5 6,041 46,738 That Time I Got Reincarnated as a Slime: Side Story ~How to Spend a Certain Vacation~ (Author) Fuse / (Illustration) Mitsuba?
6 3,968 3,968 My Tiny Involvement in an Isekai Life 10 (Author) Nu? / (Illustration) Koyoi Mitsuki
7 3,855 67,147 Classroom of the Elite: Year 3 Arc 3 (Author) Sho?go? Kinugasa / (Illustration) Shunsaku Tomose
8 3,797 13,140 Ao no Hako: Interlude (Original) Kouji Miura / (Novel) Nao?
9 3,763 24,717 Sometimes She Dere?Dere in Russian, Neighbor Alya?san 11 (Author) SanSan SUN / (Illustration) Momoko
10 3,449 3,449 Demons Crest 4: Hegemony ∽ Struggle (Author) Reki Kawahara / (Illustration) Yukiho? Horiguchi

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