Contrail

Contrail is a powerful Seeker with a scornful, imperious nature and a tendency to glare. He was Council Secretary on the High Council in the days before the great war, but left that position, along with fellow Council member Ratbat, to join Megatron's Decepticons. He possesses a cockpit in vehicle mode that is the perfect size for a smaller robot like Ratbat to ride within. This is said to be a hold-over from the Quintesson war era.

Transformers: Exodus
Contrail swore in Megatron and Orion Pax on their appearance before the High Council. He aggressively questioned them about their activities. He then voted with the other councilors for Orion to become Optimus Prime and be given the quest to find the Matrix of Leadership. When Megatron, enraged by this, killed High Councilor Halogen, declared war and called the Decepticons to follow him Contrail left with him, along with fellow council member Ratbat.

Transformers: Robots in Disguise
Sometime in his past, Contrail had employed a Cybertronian Buffaloid named Terrashock into his service and later sent him to kill some Cybertronian who crossed Contrail. After Terrashock was imprisoned aboard the Alchemor when it crashed on Earth, Terrashock was freed from his stasis pod and opted to finish his task that Contrail assigned him to do. However, Terrashock was eventually captured again by the Autobots.

Trivia

 * What exactly Contrail and Ratbat were doing is rather unclear. It seems very likely they were already of Megatron's camp, given that they leave with the rest of the "secret" Decepticons in the Council Chambers. If so, their outward aggression during procedures was probably intentional, masking leading questions to influence the direction of the meeting... But if that is so, why did they then vote for Orion Pax as the new Prime? This was clearly not part of the infuriated Megatron's plan? Yet regardless of this apparent betrayal they felt safe enough leaving with Megatron's Decepticons.