Everything was either 'Light' or 'Dark,' especially in Misthaven, and Killian was quite over it as the youth said - even the Dark Ones that lived as the little voices in his head ultimately wanted to do away with light magic, but to him, magic was neither light nor dark. Didn't intent matter? Though, certainly, considering he was a host for Darkness - of course that was how he got his power.
"It entails a lot of magic," he said, fidgeting slightly to find a more comfortable sitting position on the docks. He didn't mind Loki's closeness though - not many had been close to him lately. Those shadows lurked in his peripherals - he could see Nimue's eyes flicker in that watchful, reptilian way. "Being a host for, literally, Darkness. Looks kind of shadowy, like tendrils of black. It's within me, giving me power and immortality but also...eating away at the important parts, I suppose? If one believes a heart to be important."
He wasn't sure how he felt about it these days. "And no, I didn't possess magic before this." His hook had been enchanted to be able to take a heart, and he had aged spectacularly well thanks to Neverland and various other curses - but he didn't cast spells.