Grave Ohja

Edison Card Text
While there is a face-down Defense Position monster(s) on your side of the field, no player can select this card as an attack target. Each time a monster on your side of the field is Flip Summoned, inflict 300 damage to your opponent.
Dark Revelation Volume 3 • 2006-11-25
No targeting
No Damage Step effect
Banlist • Unlimited
Interactions
If I flip Golem Sentry while I control Grave Ohja and my opponent controls Light and Darkness Dragon, how do the effects chain?!
Golem Sentry is flipped face-up, Grave Ohja's trigger is available, and Light and Darkness Dragon is on the field.
The trigger effects go on the chain in turn order (e.g., Sentry then Ohja). Light and Darkness Dragon, as a mandatory quick effect, chains to negate the last effect. After that, Sentry can still resolve to return Light and Darkness Dragon to the hand.
Rulings
edisonformat.net
●If you control “Grave Ohja” and you Flip Summon a Flip Effect Monster, the two effects go on a chain. You can choose which effect is chain link 1.
●If you control multiple copies of “Grave Ohja” and Flip Summon a monster, the effects go on a chain and you can choose the order of the chain links.
●The second effect of “Grave Ohja” is a Trigger Effect that activates when a monster is Flip Summoned. It can be chained to.
●If “Grave Ohja” is attacked, and you activate “Book of Moon” to flip another monster on your side of the field face-down, “Grave Ohja” has already been selected as the attack target so the attack proceeds as normal.
edisonformat.com
If you control “Grave Ohja” and you Flip Summon a Flip Effect Monster, the two effects go on a chain. You can choose which effect is chain link 1.
If you control multiple copies of “Grave Ohja” and Flip Summon a monster, the effects go on a chain and you can choose the order of the chain links.
The second effect of “Grave Ohja” is a Trigger Effect that activates when a monster is Flip Summoned. It can be chained to.
If “Grave Ohja” is attacked, and you activate “Book of Moon” to flip another monster on your side of the field face-down, “Grave Ohja” has already been selected as the attack target so the attack proceeds as normal.