Insane Black★Rock Shooter

Insane Black★Rock Shooter(インセインブラック★ロックシューター, Insein Burakku Rokku Shuutaa) is another form of Black★Rock Shooter. She does not appear in the OVA. however, she does appear in the animated series. She first appeared on huke's blog and his pixiv account.

Appearance
Compared to Black★Rock Shooter, Insane Black★Rock Shooter has purple eyes with a flame of the same color emerging from her left eye and fangs. Her outfit is a black armor, covering her chest that has the black bikini top, left arm and legs. Her jacket is a torn black cape and her entire right arm is a robotic appendage holding a vicious blade. Her hairstyle resembles the same as that of BRS, she wears a black crown-like object with a white cross design which wraps around her longer lock of hair. A few chains wrap around her hair and on her waist.

Black★Rock Shooter (2012)
When Yuu sent Mato into the Otherworld, Mato was asked by a voice from nowhere if she is willing to face all of the pains and sufferings that she have gone through and will not run away from them. Mato willingly accepts, with her left eye purging blue flames. Mato merges with Black★Rock Shooter, who had stabbed Dead Master. In Mato's point of view, she finds herself in the presence of Yomi instead, and saw Black Blade went through her, causing Mato to have a mental trauma. Mato's condition appears to have affected B★RS as well, and ignites her blue flame. Seeing the corpse of the Dead Master, she suddenly became unstable and ignites a red flame, which then merges with her blue flame to create large amounts of purple flames, and turning her blue eye color purple. B★RS' iconic star breaks, matching Insane Black★Rock Shooter's iconic broken star.

Spikes start to penetrate into Black★Rock Shooter, and purple light glows from her, turning her into her iconic insane form. Nearby, Black★Gold Saw is startled by the sudden change in the area and looks behind her. Both ready their weapons and lunge at each other. Within Insane Black★Rock Shooter, Mato writhes in pain as Black★Gold Saw cuts Insane Black★Rock Shooter's right arm. Insane Black★Rock Shooter simply tears off her injured limb and Mato shrieks. She then went limp as Insane Black★Rock Shooter and Black★Gold Saw continue to fight. Insane Black★Rock Shooter uses a chain to replace her arm and hurls her Insane Cannon Lance at Black★Gold Saw. The Cannon Lance begins firing rapid-fire purple blasts while in mid-air. Black★Gold Saw avoids the attack and knocks the Cannon Lance into the ground, but the Cannon Lance deploys a turret on its underside and shoots her arm off, forcing her to retreat. She opens a rift in the floor and slides through, closing it behind her. Insane Black★Rock Shooter takes Black★Gold Saw's fallen King Saw and uses it to tear open the rift to follow her. Black★Gold Saw turns to fight again, and uses her watering can to summon several armed hooded figures to attack Insane Black★Rock Shooter.

Insane Black★Rock Shooter simply blasts through the hooded beings as she slaughters her way to Black★Gold Saw, but when she heard Saya's voice pleading to Mato, Insane Black★Rock Shooter stopped her blade right over Black★Gold Saw's head. A reaction is triggered in Mato and suddenly Insane Black★Rock Shooter is swatted away by an unseen force and pinned to a bunch of pillars.

After Saya's flashback, Insane Black★Rock Shooter screams in rage, smashes free from the pillars and attacked Black★Gold Saw again while Saya continued to plead to her. Insane Black★Rock Shooter showed no further reaction to the pleas of Saya and was in position to impale Black★Gold Saw with her own King Saw. At the last moment, the blade was jettisoned to the side where she would have killed Black★Gold Saw. It is revealed that she was pushed aside by none other than Strength. Strength's massive fists send Insane Black Rock Shooter flying into a pillar. She quickly recovers and charges Strength, but Strength slams her Ogre Arms into the floor of the Otherworld, breaking open a fissure to her world, and escapes into it with the unconscious Black Gold Saw. Insane Black★Rock Shooter leaps into the fissure and chases after them. While they leap between areas, many colors pass by.

In the tumult, they reach Strength's world. Strength puts Black★Gold Saw's body away, and she and Insane Black★Rock Shooter continue to fight. Insane Black★Rock Shooter uses her Cannon Lance to fire at Strength, but Strength manages to avoid the attack and punch Insane Black★Rock Shooter with her Ogre Arm, knocking her several yards into a wall. Insane Black★Rock Shooter follows up with her Insane Blade Claw, but Strength simply grabs the sword, breaks it with her sharp tail and throws her away. Insane Black★Rock Shooter tries to resume her assault, but Strength switches places with a large block and attacks Insane Black★Rock Shooter from behind, crushing her against the block. The scene ends with her bringing both of her fists down on the heavily injured Insane Black★Rock Shooter.

However, Insane Black★Rock Shooter regenerates and overwhelms Strength. Due to her regenerative abilities and armour, she is able to withstand both Strength's machine guns and gatling guns. Eventually Mato manages to delay Insane Black★Rock Shooter, allowing Strength to wound her, but Insane Black★Rock Shooter manages to get her Cannon Lance in front of her leg and activate the rear vulcan, wounding Mato. Insane Black★Rock Shooter is not troubled due to her high regenerative capabilities. Insane Black★Rock Shooter regains control of the fight, but Strength suddenly seems to go insane and overpowers her, grabbing the Cannon Lance and throwing Insane Black★Rock Shooter away. The two have another shoot-out, vulcans against machine guns, and Strength is again overpowered. However, she seems to enjoy this and manages to grab the Cannon Lance and punch Insane Black★ Rock Shooter in the face. She commandeers the Cannon Lance and intentionally activates all the vulcans at once to wound herself. The world they are fighting in is consumed by fire and "Strength" reveals herself to be the real Yuu Koutari, who switched places with Strength in the otherworld. Insane Black★Rock Shooter uses her Cannon Lance to propel herself over the flames to safe ground and charges at Strength, but Yuu activates several more Ogre Arms attached to her back and whacks Insane Black★Rock Shooter repeatedly on the block she is standing on and throws the Cannon Lance away. As Insane Black★Rock Shooter lies on the ground, Yuu and Strength recount their story to Mato.

Trivia

 * A popular fan theory holds that Black★Gold Saw and Black★Rock Shooter "fused" to become Insane Black★Rock Shooter (evidence to support this can be "blue+red=purple"), but this has not been confirmed in any way. A drawing has been made for this theory.
 * In the 2012 anime, it appears that B★RS turns into I.BRS from undergoing emotional trauma while merged with Mato. This suggests that I.BRS is related to BRS's mental state and is not directly related to BGS.
 * I.BRS is one of the few characters based on B★RS herself. The others are Mato Kuroi, Black★Rock Shooter Beast, and White Rock Shooter.
 * The shouting expression of WRS in the figma maybe based on I.BRS, seeing in that expression that she bares fangs, much like I.BRS.
 * The name of her weapons are Insane Cannon Lance and Insane Blade Claw.
 * The Insane Cannon Lance holds vulcans which hold tremendous firepower and fire rate. It also had a back vulcan which have a lower firepower.
 * I.BRS may have great powers of regeneration as she is seen reattaching her right arm without any worries and uses it as if nothing happened to it at all. I.BRS also don't feel any pain, no matter how fatal the opponent's attacks are.
 * Her blood is purple, compared to Black★Rock Shooter's blue blood.
 * By using the King Saw and her other weapons, she forced a portal to BGS's battlefield.
 * In the last episode preview, BRS and I.BRS seems to have been separated. The BRS shown maybe Kuroi Mato who switched positions with BRS in the same manner STR switches with Yuu.