They are the three cats of the prophecy There will be three, kin of your kin, who hold the power of the stars in their paws.
SPOILER ALERT
-Actually, Hollyleaf isn't part of the prophecy. It is actually Lionblaze, Jayfeather, and Dovepaw, who is introduced as Dovekit in Sunrise.
In Sunrise, Hollyleaf tells everyone at the gathering that they are not Squirrelflight and Brambleclaw's kits, but in fact, Leafpool and Crowfeather's.
They are also Leafpool and Crowfeather's kits, not Squirrelflight and Brambleclaw.
Leafpool and Crowfeather.
Hollyleaf's and Lionblaze's mother is Leafpool, a ThunderClan medicine cat. Leafpool has three kits with Crowfeather: Hollyleaf, Lionblaze, and Jayfeather.
Leafpool's kits are Jayfeather, Hollyleaf, and Lionblaze. They are born to her and Crowfeather, but are raised as Squirrelflight's kits to keep their true parentage a secret. Each kit plays a significant role in the later story arcs of the Warriors series.
Crowfeather is Jayfeather, Lionblaze and Hollyleaf's father.
Yes, Crowfeather and Leafpool had three kits together named Lionblaze, Jayfeather, and Hollyleaf. They kept their relationship and parentage of the kits a secret due to the expectations of their respective Clans.
Leafpool is the mother of Hollyleaf, Lionblaze and Jayfeather.
Sort of but it is confusing. But this could change because Brambleclaw and Squirrelflight are not mates anymore. Leafpool is Jayfeather, Hollyleaf, and Lionblazes's mother. Squirrelflight is Leafpool's sister. Brambleclaw is (well was) Squirrelflight's mate. Brambleclaw's father is Tigerstar. Mothwing's father is Tigerstar. So they are sort of related but barely.
No, Hollyleaf is not one of the three. Jayfeather and Lionblaze are though.
In Sunrise, the sixth book in the Power of Three series, it is confirmed that Leafpool, medicine cat of ThunderClan, and Crowfeather, warrior of WindClan, are Lionblaze, Hollyleaf, and Jayfeather's real parents. Not Brambleclaw and Squirrelflight.
yes
Crowfeather
Hated them