At least 2 "Hunter Owls" under your control will create an Attack Lockdown, with each one having 2000 ATK. (3 "Hunter Owls" will give you an Attack Lockdown and 2500 ATK per monster.)
While this card is in the Graveyard, activate "Limit Reverse" and combine it with "Inferno Reckless Summon", which then will give you 3 "Hunter Owls". Each will have at least 2500 ATK and your opponent will be unable to attack them.
Use "Hysteric Party" to summon 4 "Harpie Ladies" with this card on the field. That alone will give this card a 2000 ATK boost from its own effect, but if 3 of them are copies of "Harpie Lady 1" then that will further boost this card by 900 resulting in a total of 3900. In addition to the boosted ATK of the 4 Harpies that's easily enough for an OTK.