Depression

Blair burst into tears and ran away. 

Cadmus quietly stared after her, still burning and seething. He didn't regret anything. He didn't feel guilty. Cadmus was just deeply wounded, so he ended up taking it out on her. 

Life became more miserable after Cadmus and Blair's big fight. 

He had to admit that her shenanigans entertained him, and that having her attention all to himself felt nice. Yet, at the same time, Cadmus was despondent. His ego had been shattered into pieces, so he protected what little dignity he had left with astounding savagery. 

The people around Cadmus could sense he was spiraling into a pit of doom. They suggested that he make up with Blair. 

Of course, he refused. 'If anything, she should come begging for my forgiveness!'