Heckyl is one of the deadliest criminals, laying waste to several galaxies. On Sledge's Ship, most outlaws are kept in standard cells, but the very worst, like Heckyl, are imprisoned in specialized solitary blocks, with the cages being completely closed and reinforced with thick metallic shielding, having restraints physically attached to their bodies, and little to no contact with the outside world.
The mere suggestion by Sledge of releasing him was enough to cause an uproar within the ship, sending all of the prisoners into instantaneous panic and instilling fear even to Wrench and Fury. Despite being aware of the risk to even his own well-being, the fearless but concerned bounty hunter sends him to Earth after conceding to his offer of ruling the universe together as partners in case of a successful mission. Sledge only agrees to this because, aside from his power, Heckyl is the only one of his prisoners that looks human enough to possibly fool the Dino Charge Rangers into trying to bond the Purple Energem to him.
This plan actually goes smoothly until a rogue Wish Star intervenes, attempting to acquire the Energem to earn his own freedom. Heckyl would have attacked himself, but held back purposely, knowing that if the Rangers saw him, it would ruin his plans. After Wish Star is defeated and Fury successfully retrieves the Purple Energem, Heckyl attempts to explain himself, only for Sledge to declare their partnership over and narrowly blast him back to his cell with a shot from his now Energem-enhanced blaster.
1.) Who I think he might be
"He gave me life. Life you stole from me. And now you will repay it with your own!"
―Zeltrax revealing his hatred of Tommy Oliver[src]
Zeltrax, previously known as Terrance "Smitty" Smith, was one of Mesogog's henchmen.
An evolved version of Zeltrax (the version as seen in Zyuden Sentai Kyoryuger vs. Go-Busters: Dinosaur Great Battle! Farewell, Eternal Friends) was seen in a teaser for Power Rangers Dino Super Charge. However that does not confirm whenever Zeltrax would be seen in the series or not.
2.) Enter from Go-Busters
Heckyl bears similarities to Enter from Tokumei Sentai Go-Busters; both have flamboyant personalities, using a lot of expression and hand gestures in their speech, and both wear similar, stylish, colorful clothing with goggles around their neck and finger-less gloves. They can also transform into armored versions of themselves.
This might be due to the fact that Dino Super Charge is reported to have elements of Go-Busters, and that Heckyl may be Enter's PR counterpart.
Ferocious Knight D (獰猛の戦騎D Dōmō no Senki Dī?), also known as Deathryuger (デスリュウジャー Desuryūjā?) is the main antagonist of the Zyuden Sentai Kyoryuger: Gaburincho of Music. He was the partner of Zyudenryu Tobaspino, only because he forced Tobaspino to forge a partnership with him.
Gaburincho of Music
One of the Deboth Army's first Knights, D wreaked havoc on ancient Earth. He fought against Torin and the Zyudenryu in the past. Attempted to control Tobaspino to wipe out the rest of the dinosaurs by driving it insane, Meeko's ancestor rose up and quelled Tobaspino's rampage and bloodlust. Tobaspino then defeated D with a stomp as both fell into a deep slumber. Reawakening in the present by Chaos and given fake Kyoryuger powers with the Deathryuger Zyudenchi, D now seeks revenge and plots to wipe out all life on Earth.