I don't know if this was stated, but is he really a Decepticon? I noticed while watching Predacons Rising, that Unicron called the Autobots "Minion of Primus" now are the Decepticon also considered despite being "The Bad Guys" and want peace through tyranny, considered also "Minions of Primus" as stated by Unicron? I mean why didn't Unicron tried to kill Predaking, Skylynx, Darksteel, Starscream when he had the chance? instead he just injured them.

 

I doubt Megatron named his army after Unicron. I remember Unicron was hunting Optimus Prime, and the rest were not important, I think.
I put Unicron in my Polls into the Dcepticon's sections just because he is "opposite" to Autobots.

 

No Unicron is not a deception, though for marketing purposes he is normally listed as such due to being a bad guy

 

Unicron referred to Optimus as a "disciple of Primus", referring to his status as a Prime and a member of the Thirteen. He called the Autobots the "minions of the Prime", but if he did say Primus, he was just referring to them as such because Optimus was a disciple of Primus.

He flat out rejected Megatron's offer to serve him, deeming him scum under his feet. The only minions Unicron will command are mindless Terrorcons and husks.

As for why he didn't kill Darksteel and the rest, it's just because they still had a role to play in the plot, and Unicron saw them all as insects anyway, and just swatted them away without legitimately deadly force.

 

So basically Unicron will kill whoever stands in his way, whether it's Autobots or Decepticons.

 

Most likely.

 

My own take is that he's a megalomaniac and wanted an audience for his next display of power. The guy is all ego, all the time.

I'm sure he found Starscream's response gratifying.