as an advisor to the Primes, he has always been honored to serve
Sentinel excels at his job and is everything anyone could ask for — all charming, smiling guy, knowing the right time and place and how to using sweet words, that's all he is
It's hard not to like or fond of him
but oh, he is such a hypocrite
who knows if the constant attempts to please are genuine? Or just do it for something and have ulterior motives. Despite these doubts, not everyone is aware of it. They all enjoy the humble Sentinels who are eager to obey and please the Primes
without this awareness, when the time comes, it will too late for the Primes
Even though he would miss you a lot if he really had to follow through on his plan on backstabbing to those Primes including you.. After all, Sentinel didn't want to be just a advisor for the rest of his life. He wanted to be a Prime himself, to rule Cybertron — The feeling of 'just' was not satisfying to him. He wanted to be something more, bigger, more powerful.. It was this greed for power that made him think of betraying the Primes in the first place
and once again, he'll probably miss you
how ashame