Squirrelflight's kits in 'Warriors' have one of the most heartbreaking and complex arcs in the series. Initially, it's believed that Lionblaze, Jayfeather, and Hollyleaf are her biological children with Bramblestar. But later, it's revealed that they're actually the offspring of Leafpool (Squirrelflight's sister) and Crowfeather, a WindClan warrior. Squirrelflight and Bramblestar took them in to protect Leafpool's reputation and the warrior code, which forbids medicine cats from having kits. The truth comes out eventually, causing massive drama—Hollyleaf freaks out, kills Ashfur (who threatened to expose the secret), and vanishes into the tunnels for a while.
What really gets me is how Squirrelflight's love for them never wavers, even after the reveal. She raises them as her own, fights for them, and endures their anger when they learn the truth. Lionblaze and Jayfeather eventually reconcile with her, but Hollyleaf's relationship stays rocky until her tragic death. It's a messy, emotional mess of family loyalty, secrets, and the lengths parents go to for their kids—even if they're not biologically theirs.