The Dairangers last names are their star designations.
Meaning Ryo is Ryo Tenkasei, Daigo is Daigo Tengensei, etc. Hey, the Gorangers names spelled out Cassiopeia, so why not. The real Shadam is still out there somewhere.
He knew that the power of the Gorma Emperor causes insanity, so instead of taking it directly, he created a proxy to use in his stead. This also explains how the Gorma were able to revive 50 years later. Alternatively, the real Shadam gave up on becoming the Gorma Emperor.
Shadam realized that the conflict between the Dai and Gorma Tribes would only continue as long as the Lai-Lai Jewels and the Earth Shaking Jewel remained on Earth, he created clay puppets of all the leaders of the Gorma Tribe including himself and orchestrated events so that his clay puppet would rapidly escalate the conflict until Daijinryu intervened and threatened to destroy the Earth, forcing all the Jewels to scatter themselves across the planet to appease him. Daijinryuu is an Inevitable.
Inevitables are powerful mechanical beings, Lawful Neutral in alignment. Their purpose is to enforce natural laws. Daijinryuu is extremely powerful, mechanical, and definitely Lawful Neutral, and exists to maintain the balance between opposing KiRyoku and YouRyoku forces.The Dairangers are Force-Sensitives.
Their Ki powers are basically the Force, and one of their BGM tracks sounds suspiciously like the Imperial March.