Sunny's soul had been dealt a severe blow, losing one of his Shadow Cores.
There were obvious consequences, like the dull pain he was experiencing and his diminished power. The craziest of his shadows was gone, making him feel sad and a little depressed… as if a part of him was gone. It was, quite literally.
'I'll miss that guy...'
His feelings regarding the demise of a loyal shadow aside, there was also the fact that he was once again a Terror, meaning that there was less of him out there. He could be in fewer places at the same time, could empower fewer things, and if he wanted to focus all his power in one place, the augmentation would not be as potent as it had been before.
As for the soul wound… it wasn't as bad as it could have been. Losing a single core was not going to kill a Titan, and especially not Sunny — his soul was especially tenacious, after all, and would slowly recover if even a little piece of it remained intact.
