In the 3DS version, the darkonium slime appears as the boss of the Kooky Keep DLC Tablet. In the place of its familiar particle ray, it will use the devastating Big Banga ability against the party, wiping out parties of unprepared adventurers. Thankfully, the damage can be reduced with the help of Insulatle and the slime's low MP pool means it will only be able to use it once.
There's not a single spell that can scratch these superslimes, who crush the competition with a powerful particle ray.
They spend their days proudly polishing their faultless facets and likening them to twinkling stars and priceless pearls.
Darkonium slimes make their first appearance in the main series, being found exclusively in high-level ruins or ice treasure maps. They are impervious to all spells and status ailments, and dodge attacks often. They are very vulnerable to Falcon Slash and basic attacks from the Falcon Blade and Über Falcon Blade because they hardly ever dodge these strikes. They can attack normally, hit all party members by squishing them or hitting them with their particle beam, and can cast Multiheal.
It should be noted that Darkonium slimes are not treated as Gem/Metal slimes when resolving physical attacks, so using Metal Slash is unnecessary, despite their resemblance to Gem slimes and Platinum king jewels.
The Darkonium slime is a resilient two-slot Rank A monster. It is synthesized through the combination of a Slimecicle and a Coal slime. In this game, it has the metal body trait, necessitating the use of anti-metal monster tactics.
Darkonium Slime appears as a S-rank monster of the Slime family, appearing on its own banner alongside Toxic zombie. It can be faced as a boss in Chapter 6, Episode 9 in Part 4 of the main storyline.
High Minded / Stats Up All Element Res +5 / Stats Up Crimson Brilliance: When attacked by enemy: Heals 10% of the user's max HP. / Darkonium Ray Potency +5% / Stats Up All Element Res +5 / Stats Up Max HP +100 / Darkonium Ray Potency +5% / Stats Up
Perks
Basic perks
AGL +20 DEF +20 Hard Metal Body: Reduces damage by 45% and raises ability MP cost by 30%. Darkonium Ray Potency +2%
Leader perk
Raises martial potency of slime allies, including itself, by 20% in a 5x5 square around it.
Awakening perk
High Minded: Action start on odd turns until turn 10: Raises AGL, and martial potency/recovery for 3 turns.
Darkonium slime (スライムマデュラ, Suraimu Madeyura ) 
Darkonium slime 
Darkonium Slime (スライムマデュラ Suraimu madeyura)
A darkonium slime in X
Joker polygon model.
Appearance in Super Light.
A darkonium slime in Tact.
