Oncat is a scrawny, orange, tabby that has taken a liking to Harshaw.
Oncat had made her way to the White Cathedral somehow, and started following Harshaw around, slinking between his legs or clinging to his shoulder. She is known to scratch Harshaw a lot, and accompanied him when Alina Starkov escaped the Cathedral with the Grisha. When Harshaw was injured, she clung to him, yowling, and was also present as the party hunted the Firebird. When the Grisha entered the Shadow Fold, Harshaw left Oncat with Misha. After Harshaw's death on the Fold, and the destruction of the Fold, Oncat was with Misha, Alina, and Mal as they passed through to Kribirsk.
Oncat lives with Misha, Alina, and Mal in Keramzin. Misha brought the cat to the reunion with the Darkling, and she seemed quite content to see Zoya again. The cat was unharmed after the Darkling attacked them and ultimately escaped.
- Oncat is Kaelish for cat.