Nami and Luffy were walking back to the Sunny when they were attacked by bounty hunters. Luffy (while protecting Nami) got shot from a SeaStone bullet and fell into the sea. Nami seeing this started to panic instantly and tried to jump after him but got surrounded and just called:

-Luffy!
On the Sunny the crew heard Nami screaming and started to run to see what happened. When they arrived Nami give sigh in relief upon seeing them, then explained:
-Guys! Luffy is in the water ...he got shot...
She was cut off by Zoro as he called to the one closest to the water:
-Love-Cook! Go for him! The others beat them!
The crew were fighting until Sanji finally came back up with Luffy
-Hey, This don't look good at all! -Sanji called when he got out of the water with Luffy and they could easily hear the worry in his voice as he spoke.

Luffy looked like he was dead. The crew was shocked. Zoro was the first to spoke:

-Go to the ship everyone! Chopper...
But the young doctor didn't need to hear the order so he nodded:
-I know.
Zoro nodded too as he added:
-Ok then I think I still have a little work here.
Around him a dark demonic aura started to appear the others just nodded and started to run. But they all were throwing glances back at the swordsman then Usopp started:
-What happend to Zoro? I mean he aren't usually like this, right? Something is off...
Nami let out a sigh then said:

-If what is happening is what I think it is then... Let's just say that we need Luffy as soon as possible.
Everyone turned to her in surprise at the words and Chopper asked:
-What? ...What do you mean Nami?

-That aura I saw it once before...Zoro.. He was known as Demon at the East Blue and they had a reason to call him that ...When I first meet them I just thought that they had no reason at all but after that..one day...Well now I understand why they call him that ...We were in a jungle when Luffy was attacked and got a serious injury...then I felt that aura and from that point I couldn't reach Zoro, he just couldn't hear me ...If Luffy didn't regain consciousness and stoped him those guys would be dead for sure. He didn't care how they pleaded he was merciless..

They arrived to the Sunny and Chopper instantly took care of Luffy. The others decide to go back and try to stop Zoro while Sanji guarded the Sunny and Chooper. When they reached the battelfield they were shocked. There were the bounty hunters lying in their own blood, their boss the only one on his feet still, but he was in bad shape too. He tried to escape but Zoro wouldn't allow it to him. The crew tried to stop Zoro but their voice didn't reach him at all. Whatever they said Zoro acted as if they weren't even there. They thought that there is no hope at all when Zoro was about to kill the man but then suddenly Luffy's voice rang out:
-ZORO! STOP! It's enough. Everything is fine now. Lower your swords.
In that moment Zoro stoppped the aura slowly disappeared and Zoro walked to Luffy's side. Luffy smiled at the swordsman and turned to his other crewmates:

-Ok , Everybody back to the Sunny!

They headed back to the ship ..Zoro and Luffy sat down on the deck the others went to the kitchen

-Captain-san is amazing ...-said Robin the others look at her

-I mean we all tried to stop Swordsman-san but ...we had no chance at all then he appered and just said 'Stop' and he did and his demonic aura disappeared too

Everybody nodded then Nami said:

-I can't believe how much he changed in few minutes ...I mean just look at him now..
They looked at the pair on the deck. The duo was speaking and laughing . They all smiled at them and then Chopper said...
-At least that demonic side of Zoro just our enemies problem even though it's scary.

Everybody looked at Chooper as if to ask 'What? ' so he started to explain:

-I mean when he gets like that he sees Luffy's enemies as his, right? That's why even though we all were there too he didn't attack us at all and that aura too it was as if it wanted to protect us and Luffy it is just felt like that to me...
-We understand -Franky said and the others nodded too. They didn't realize it before but Chopper was right about that. Zoro might didn't stop because of them but he never once moved to hurt any of them. Nami then smiled and teased:

-Well it seems Luffy has a demon for himself in this crew too. If things go on like this I might start to feel sorry for our enemies.

They all nodded at this. Then smiled as they agreed to join the other two on the deck. Non of them bothered to bring the happenings up. It wasn't worth it. Everyone of them were save that was the important thing.