Ace's tattoo.

Ace is Luffy's brother in law which meet luffy the first time at a young age. He made his tattoo on his right arm and named it ASCE with the S crossed out with an X. Without the S crossed with an x the tattoo, is his name ACE. 

The S crossed as a tattoo means allot to Ace because, when he was young his best friend was Sabo. After some time Sabo went out to sail in the ocean with a small ship. when he exactly set sail people bombarded the ship which he was in and then died on the spot. The S with an X on it is because, his name was Sabo so he decided to make his first letter of his name with a cross bone as his pirate flag. Ace made a tattoo of his flag to keep him in his memories.

The other tattoo which Ace have on his back is his pirate crew flag symbol. He's not the captain of the crew but he's a crew member, subordinate and the tattoo and flag is of the white beard name which he's in.

Ace's ASCE tattoo is first shown at 0:01 minutes and the white beard tattoo in the video first is shown at 0:03 minutes.