Thatch was the commander of the 4th Division of the Whitebeard Pirates.
It was revealed that, Thatch found the Devil Fruit that Blackbeard was after (the Yami Yami no Mi). This Devil Fruit was the very reason that Blackbeard joined the Whitebeard Pirates, so he killed Thatch and ran off with it.
First Appearance: Chapter 440; Episode 325
Source:
Power
91 / 100
Speed
76 / 100
Technique
88 / 100
Intelligence
87 / 100
Cooperativeness
61 / 100
One Piece
Supporting
Madono, Mitsuaki