Gillian's Aura Experiments on Grimm Gillian Asturias, using her Semblance (Aura Siphon) from the Before the Dawn novel, attempted to transfer Aura to Grimm to study the effects on soulless beings. The experiment failed dramatically: Grimm lack souls, so they aggressively drained her Aura instead, nearly killing her. This highlights the fundamental incompatibility between Grimm (as voids of destruction) and Aura (tied to the soul and positive emotion).
SDC Experiments on Grimm (Arma Gigas) The Schnee Dust Company experimented by mutating a Geist Grimm and infusing it into a replica of Nicholas Schnee's armor, creating the Arma Gigas. This appears aimed at weaponizing or controlling Grimm elements for combat or summoning purposes. The result is a durable, possessable armored entity that Weiss Schnee has fought and later summoned herself, blending inorganic material with Grimm essence for enhanced utility.
Cinder's Shadow Hand (Grimm Arm Graft) After losing her left arm at Beacon, Cinder received a grafted Shadow Hand from Salem via an unknown (likely magical) method. Salem's magic modifies Grimm bodies, enabling this attachment. The graft grants elasticity (extending meters with maintained strength) and the ability to forcibly absorb/assimilate Maiden powers. Weaknesses include no Aura protection on the Grimm part (retaining soulless nature), extreme vulnerability to Silver-Eyed powers (causing intense pain), black smoke "bleeding" when damaged, and Salem's remote control to inflict agony as punishment. The graft has regrown when severed and spread scarring upward, showing ongoing integration or corruption.
The Hound (Original, Possibly Summer, and Salem's Plans for Ruby) Salem created The Hound as an intelligent hybrid Grimm using a captured Silver-Eyed Faunus as its core. It adapts by shape-shifting (growing wings, limbs), speaks, tracks targets, and serves Salem's commands. This fits her broader experiments to evolve Grimm by fusing human/Silver-Eyed elements for intelligence and utility, shifting from killing Silver-Eyed Warriors to capturing them for hybrids. The core's Silver Eyes explain its smarts but also its vulnerability. Ruby wonders if Summer Rose suffered a similar fate (hinted strongly in canon), and Salem plans to experiment on Ruby similarly—to harness Silver Eyes in controllable Grimm forms.
Virtual Grimm In Justice League x RWBY: Super Heroes and Huntsmen, Part One, Arthur Watts and the AI Kilg%re created Virtual Grimm in a digital space. They mimic Remnant Grimm's hostility and can absorb Dust to disable opponents. Kilg%re controls or possesses them. They differ by being fragile (often one-hit destruction), unstable (glitching in/out, leaving remnants), and purely digital—designed for trapping/combating heroes in a simulated environment.
Artificial Grimm In Justice League x RWBY: Super Heroes and Huntsmen, Part Two, a digital Watts (with Kilg%re) produces Artificial Grimm on Earth. These are more physical replicas of Remnant Grimm, plus new variants, with programmable behaviors, fast adaptation, strategic cooperation, and custom powers (e.g., shields, reboot/revive, hero counters like Kryptonite generation or power absorption). They dissolve into goop on death. They're more effective than virtual versions but hackable (e.g., by Cyborg) and vanish without Watts/Kilg%re's presence/power.
Mutant Grimm Dr. Merlot (from RWBY: Grimm Eclipse) used a glowing green serum (from a radioactive island substance) to genetically modify Grimm like Creeps, Beowolves, and Death Stalkers. Mutants gain superior strength, size, new attacks (explosions, crystal-like bone spikes), and green eyes/markings/internal glow. Merlot viewed Grimm as a "superior species" for Remnant's future, but his experiments caused disasters (e.g., aiding Mountain Glenn's fall) and were stopped by Team RWBY/JNPR.
Jabberwalker (God of Darkness Experiment Before Grimm) The Jabberwalker, from Volume 9 and the Ever After, was created by the Gods (with the God of Darkness heavily favoring and reviving it) as an antithesis to the Curious Cat. It "finishes" broken Afterans by devouring them permanently (preventing Ascension/rebirth). It has speed, strength, agility, limited speech (narrating actions), and sentience. As a brutal prototype favored by Darkness, it influenced Grimm design—appearing similar and serving destructive balance before Grimm's creation on Remnant.
Overall Comparison These experiments show varied approaches to manipulating Grimm: divine origins (Jabberwalker as a precursor for destruction/balance), magical enhancement/grafting (Salem's hybrids like Cinder's arm and The Hound for power and control), scientific mutation (Merlot's serum for physical superiority), corporate weaponization (SDC's Arma Gigas), semblance-based trials (Gillian's failed Aura infusion), and technological/digital replication (Virtual/Artificial Grimm for simulated or programmable armies). Common threads include amplifying Grimm's destructive nature, adding intelligence/adaptability (e.g., Hound, Jabberwalker, modified Artificial), and retaining core traits like hostility and dissolution on death (smoke, goop, fade). Many backfire—Gillian's drain, Merlot's disasters, graft vulnerabilities, hackable Artificial Grimm—exposing Grimm's uncontrollable essence. Salem's work (grafts, hybrids) advances most toward human-Grimm fusion for strategic dominance, while others explore curiosity, power, or tech limits. Divine (Jabberwalker) and magical (Salem) feel "organic" to Grimm's lore, while scientific/digital ones highlight human hubris in replicating or improving nature's monsters.
(Also Artifacts control Grimm implies someone else tried this.)