I'm writing from a third person viewpoint. I have a character who does not have a name. He is simply known as "The Sentinel". In fact, that is the only introduction he gives for himself. So when I'm writing a scene where he interacts with other characters, I don't know whether to capitalise the first letter of his title or not.
e.g. sentences -
Adam stared at the Sentinel for a long hard second.
(OR)
Adam stared at the sentinel for a long hard second.
The Sentinel stood quietly, surveying the whole thing.
(OR)
The sentinel stood quietly, surveying the whole thing.
Surprise leapt on the Sentinel's face but he covered it well.
(OR)
Surprise leapt on the sentinel's face but he covered it well.
Also, extending the question, should the "the" before the title be also capitalised?