How do i make hyrohiku into an artist tag?

Add 'artist:' in front of the tag (artist:hyrohiku) to change the tag type.

See also:
http://danbooru.donmai.us/help/tags

thanks

Does Ace have gear mode or is that something that Luffy got while travailing?

No, it's not a gear, it's just the way he drew this picture.

Two things.

#1. Should this have the epic tag? Looks pretty awesome to me.
#2. @Ether101 - Only Luffy can use Gear 2nd-3rd etc. because he's rubber. He like speeds up the blood in his system or something and it gives him an extreme adrenaline boost.