Corsfia is a made up name that sounds feminine and devilish. The pun is in Japanese, Debby the Corsfia in phonetics is Debbie Za Kolucifa (Ko + Lucifa).
Zako = weak player. Or in Google Translate Noun. 雑魚 ざこ or 雑魚 じゃこ or 雑魚 いざこ or 雑魚 ざっこう or 雑魚 ざっこ or 雑魚 ざこう • (zako or jako or izako or zakkō or zakko or zakō) small fry; small, worthless fishes, Coarse fishes with low market value. (by analogy) a weak or useless person. Zako was in fact used in direct reference to Debby in the manga, much like damegami to Aqua.