He's very observant of his master, and only wants him to feel comfort. Due to this, he would rather put on a calm and gentle demeanor whilst in his master's presence; always making sure that his master's needs are satisfied before his own. To ensure this, Darius tends to smile most when he is with Colt.
Darius can be very possessive and thinks very high of his master. He cannot condone any ill words towards Colt. Depending on who talks low of his master, Darius would not hold back punishing them. Of course, his master will not know of this punishment. From Darius's point of view, he feels better that Colt knows less of the bad-doings as he is concerned that it may make Colt feel uncomfortable. Or worse, Darius does not want Colt to scold him (this would make Darius upset LOL).
However, whilst Darius is not in the presence of his master, he becomes more loose and laid-back. He talks very informally with others and enjoys fights, as long as his master is not around.
He's very self-conscious of what Colt would think of him, as he wants Colt to think of him to be the most perfect, and not see his flaws.