Rimuru's Crystal.

An essential item to upgrade Rimuru's Resonance Level.

Sources

Limited Events

Camping with A Slime

Upgrade (Rimuru's Development Bundle): x190 (Free), x800 (Pack 💵), Total: x990

Artifacts
UR Artifacts: Cloak of Levitation • Golden Apple • Horn of Plenty • Magic Lamp • Mask of Nobility • Meowna Lisa • Mermaid's Tear Event Artifacts: Allucia's Sword • Anti-Magic Mask • Beryl's Sword • Diablo's Doll • Dragon Knuckles (Replica) • Surena's Dragon Dual Blades • Shuna's Doll
SSR Artifacts: Lucky Horseshoe • Magic Pendant • Master Key • Psychical Orbuculum
SR Artifacts: Ancient Slate • Preliminary Textbook
R Artifacts: Felling Axe
N Artifacts: Goblin Club

Avatar Frames
UR Avatar Frames:
SSR Avatar Frames: Comeback Festival

Fragments
Artifacts
UR Fragments: Magic Sword Laevatein Fragment
Characters
UR Fragments: Limited Character Fragments: Beryl Fragment • Shuna Fragment
SSR Fragments: Anne's Fragment • Augustine's Fragment • Baity's Fragment • Denier's Fragment • Emosen's Fragment • Ida's Fragment • Jewlry's Fragment • Kosuzu's Fragment • Lilith's Fragment • Lina's Fragment • Loya's Fragment • Sera's Fragment Limited Character Fragments: Allucia Fragment • Diablo Fragment • Milim Nava Fragment
SR Fragments:

Chat Bubbles
UR Chat Bubbles
SSR Chat Bubbles: Happy Camping
SR Chat Bubbles:
R Chat Bubbles:
N Chat Bubbles:

Costumes
★5 Costumes:
★4 Costumes: [Acedia] New Adventurer Pro • [Anne] Storm Slasher • [Augustine] Magic King • [Baity] Afternoon Tea by the Pool • [Bren] Speech of Royal Heir • [Bridget] Fallen! Shining Heart! • [Bridget] Mazarine Waltz • [Denier] Queen of the Night • [Emosen] Sea Explorer! • [Eter & NAL] Airborne Savior • [Holly] Playing with Water • [Ida] Tales Under a Maple Tree • [Ida] Winter Night's Tale • [Iori] The Joys Bringer • [Ira] The Archdemon's Arrival • [Jewlry] Bug Catcher Jewlry! • [Jewlry] Foodie Night • [Jewlry] Mascot Trainee Maid • [Kagura] Fleeting Glimpse • [Kosuzu] Another Round! • [Lilith] Caged Bird • [Lilith] Dream of a Giant • [Lina] Run Toward Happiness • [Loya] Exotic Maid Doll • [Lux] Scarlet Lady • [Mammon] Rest in Wild • [Mescal] Return of the Victor • [Myner] After Work Drinks • [Nip] Kitty the Rescuer • [Sera] A Gift Just for You • [Sera] Coco Bowl and Service • [Sera] End of the Festival • [Super] Fate Musician • [Thalia] Stunning Entrance • [Tigirl] Water Gun Showdown! • [Trady] Owner of the Yacht
★3 Costumes: [Baity] Unexpected Doctor • [Belle] Azure Wanderer • [Catherine] Witch in the Wind • [Chihaya] Vibrant • [Cimitir] Field Sketching • [Ena] Archmage of Light • [Ena] Diligent Genius • [Freyja] Secrets after Work • [Gina] Highly Praised Business! • [Isatilra] Charming Flower • [Kosuzu] Catnap by the Sea • [Lina] Perfect Trainee Maid • [Loya] Dark Heart, Transform! • [Lulu] Royal Cheerleader • [Mammon] Emerald Glinting • [Mater] Sculpt Perfect Curves • [Maynard] Dreamy Bubbles • [Melody] Wisteria Beauty • [Merry] Shy Cheerleader • [Nene] Morning after Overtime • [Ookami] A Nap on Calming Waves • [Paat] Glacial Glint • [Sadako] A Loving Painting • [Sofia] Cool Feast • [Stephanie] Open the Treasure Chest! • [Vivian] A Bold Change • [Vlad XIII] The Noble Escort • [Wenreesa] An Unexpected Outfit • [Wenreesa] The Silent Dealer
★2 Costumes: [Gina] Talented Gardener