Banaro Island is an island that was ransacked by Blackbeard and his crew. This Island is quite close to Water 7 but isn't on the route of the Sea Train.
Banaro Island is known for Banana Rock. this island is known to have huge rocks that face up in different directions. It is next to the town where Ace and Blackbeard fought, this island was destroyed. The place where Ace and Blackbeard fought is unnamed but it is known to have an old Wild West theme. It was destroyed by Blackbeard.
When the Blackbeard Pirates had invaded Banaro Island, Ace found him. Blackbeard greeted him as his former Commander but Ace said it was an insult because of what Blackbeard had done( him killing Thatch). Despite this Blackbeard offered Ace to join his crew and capture Straw Hat Luffy. Ace refused revealing that Luffy is his younger brother which shocked Blackbeard and that Ace wouldn't allow him to hurt his younger brother.
At that time Van Augur shot Ace but the bullets went through Ace's body and when Jesus Burgess tried to lift a building and tried to crush Ace with it, Ace used his devil fruit powers to destroy the building. Blackbeard orders his crew to stand down as they are no match for Ace and tells his crew to leave town while he takes care of Ace. Blackbeard then revealed to Ace on why he killed Thatch.
Blackbeard goes ahead and uses his devil fruit powers to swallow the whole town and intentionally misses Ace. He then releases all the ruins of the town, revealing the true nature of his power. However Ace is unimpressed and attacks Blackbeard but is surprised that the attack couldn't pass him even though is a Logia type user.
After the initial shock of the attack, Blackbeard consumed all the flames with his dark aura and then told how his devil fruit power could absorb anything. He used his Dark Vortex technique to grab Ace's body and activated his devil fruit's most deadliest power; the power to nullify and Devil Fruit's power when touched. After Ace's devil fruit powers were nullified, Blackbeard punched him really hard and smashed him into the remains of the town.
Blackbeard then boasts about the fact that he exposed the weakness of all devil fruit users and he can't be defeated as his fruit is the 'Devil' itself. Ace then pointed out the fact that Blackbeard can only nullify the devil fruit powers if he has physical contact with the user, to prove Ace wrong he attempted to draw Ace in again but Ace countered it by launching two fire lance into Blackbeard's chest, to which Blackbeard reacted by punching Ace on his neck.
Ace was thrown into the town's remains and before Blackbeard attempted to consume the flames with his powers, Ace quickly retaliated as he knew that if he didn't he would get severely injured.
The battle continued on and the Banaro rocks collapsed due to the amount of power that both Blackbeard and Ace were using. At last Blackbeard and Ace were both exhausted, especially Ace who was truly worn out. Blackbeard offers him one last time to join his crew but Ace refuses.
Blackbeard, impressed with Ace's strength, expresses how disappointed he was and said that they could have taken over the world together. After saying this, Blackbeard unleashes a massive dark shroud, and Ace at the same unleashes his own ultimate technique. Both of them were ready to fight to the death which caused a massive explosion of energy that almost wiped out the whole of Banaro Island.
It is unknown if Banaro Island had anyone living on it. The Blackbeard Pirates had temporarily come to this Island to stock up on supplies.
Banaro Island is located in the Grand Line.