Liokaiser is on the right.
Omegus has covered the basics of who these guys are. Basically, as he says, Liokaiser is the secret combined form of the Breastforce, who takes near on twenty episodes to finally show up. He's a ruthless and extremely powerful gestalt, arguably the most powerful one ever shown in
TF (though the recent depictions of Monstructor, in the Dreamwave profile books and
TF / GI Joe Black Horizon, would make him even more powerful!).
Liokaiser has a decent amount of attacks. In the show he wields a three part rod that can shoot spiked disks from its tip, extremely devastating they did a lot of damage to Star Saber in their first encounter. Victory Saber, the powered up combination of Star Saber and Victory Leo, was really the only
TF capable of fighting Liokaiser on a level footing, although his effectiveness was compromised by the writers somewhat, who made all the Decepticons pretty much bumbling comic relief to a greater or lesser extent by this point. He was easily the most efficient Decepticon in that show, but that wasn't saying a lot.
I like to compare him to how Devastator was initially portrayed. Liokaiser has that kind of "oh heck, now we're in for it" impact whenever he shows up.
One last image to go out on - Liokaiser VS Star Saber (Robot Masters version):
