New Game Release! "I've Been Killing Slimes for 300 Years and Maxed Out My Level: Witchcraft" is now live on G123!

Join now and claim up to $700 worth of in-game items in the Launch Start Dash Event!

CTW Inc. is excited to announce the official launch of G123’s latest game, "I've Been Killing Slimes for 300 Years and Maxed Out My Level: Witchcraft."

Enjoy the new "I've Been Killing Slimes for 300 Years" game on both smartphone and PC!

Based on the hit anime, this beloved series is now a game for the very first time! Dive into a laid-back, fluffy battle RPG—"I've Been Killing Slimes for 300 Years and Maxed Out My Level: Witchcraft" officially launches today! To celebrate, enjoy launch-exclusive in-game events and campaigns where you can earn up to $700 worth of items. Don’t miss out!

Play Now

In addition, the official service launch trailer has been released on the G123 official YouTube channel. Be sure to check it out!

Start now and get up to $700 worth of in-game items! Launch Celebration Event Now Live!

To celebrate the official release of "SlimeWitch300", a luxurious Start Dash Event is currently underway!

Log in daily, complete quests, and progress through the game to earn a wide variety of rewards. Within just 30 minutes of play, you’ll recruit Laika to your party, and in just 3 days, you can earn up to $700 worth of items. Don’t miss this chance—start "SlimeWitch300" now and kick off your adventure in the best way possible!

New Game Release! Giveaway Event!

The official launch of "I've Been Killing Slimes for 300 Years and Maxed Out My Level: Witchcraft" is here! To celebrate, we’re holding a special Amazon Gift Card Giveaway! The more you enter, the higher your chances of winning!

▼ Event Prizes
Amazon Gift Card $10 x 10 winners in total

▼ Event Period
Event Period: 7/9 11:00 up to 7/31 23:59 (UTC+9)
Winner Announcement: 8/5 12:00 (UTC+9)

Visit & Follow the Official X

A Chill Battle RPG Where You Level Up with Family!

This is the first browser game adaptation of "I've Been Killing Slimes for 300 Years and Maxed Out My Level." But this time, Azusa has mysteriously returned to Level 1…?!

Visit iconic locations from the anime, and help Azusa become the strongest "Witch of the Highlands" once again!

"SlimeWitch300" is available only on the G123 platform. It’s an HTML5 game you can enjoy right from your smartphone, tablet, or PC browser—no downloads required! 

With full idle features, you can play your way: grind at home on PC, or level up casually on mobile anytime. We hope you're looking forward to diving in!

Game Info

Game Title: I've Been Killing Slimes for 300 Years and Maxed Out My Level: Witchcraft
Genre: Laid-back Battle RPG
Price: Free to play (in-game item purchases available)

■What is "I've Been Killing Slimes for 300 Years and Maxed Out My Level"?

Based on the light novel by Kisetsu Morita, the series has sold over 3 million copies to date.

It was adapted into a TV anime in April 2021, with Season 2 airing in April 2025. This beloved isekai (another world reincarnation) series features adorable characters and a relaxing, fluffy world that fans can’t get enough of. Its heartwarming slice-of-life storytelling and lovable cast have made it a fan favorite, leading to multiple manga adaptations and spin-offs. A true gem of the slow-life comedy genre.

©Kisetsu Morita-SB Creative Corp./slime300 project2
©CTW, INC. All rights reserved.

*All company and product names mentioned herein are trademarks or registered trademarks of their respective owners.