Shigematsu was the Vice-President of the IGO, whos power in the IGO is only superceded by Ichiryuu himself. It's later revealed that Shigematsu was a spy who infiltrated the IGO under the employ of the rival organization NEO.
Not much is known about Shigematsu's origins. He was however seemingly a close friend of Mansam's before defecting to the NEO organization.
Shigematsu is a secondary antagonist created by Shimabukuro Mitsutoshi for the series Toriko.
Shigematsu was originally the Vice President and Second in Command of the IGO. However he switched his allegiance to NEO. It can be assumed that he was defeated and brainwashed by Joa in order to cause him to defect.
Shigematsu is a tall and muscular middle aged man with, slightly tan skin, a full beard and mustache and dark brown hair, with a streak of gray down the middle.
Shigematsu appears to be a stern man. When there was talk of Heavenly King Zebra being released from Honey Prison, Mansam supported the idea as did President Ichiryuu. However Shigematsu did not and felt Zebra should remain incarcerated. Eventually Ichiryuu overruled this and ordered Zebra's release.
Mansam - The two had shared a seemingly decent relationship and they were closest in rank within the IGO, Shigematsu being the second in command and Mansam being third in command. However after defecting to the NEO organization, Shigematsu back-stabbed Mansam, figuratively and literally.
Shigematsu meets with Mansam and requests his assistance. He expected that the Bishokukai would come to take back their destroyed GT Robo and wanted Mansam with him in case the opponent was too strong. Indeed, Bishokukai Vice Head Chef Grinpatch arrived, however he was not someone capable of defeating the powerful duo. Shigematsu and Mansam powered up and that alone was enough to make Grinpatch realize that he was outmatched and he retreated.
Shigematsu abruptly arrives where Mansam is battling against the numerous Giant GT Robos. Before Mansam even takes notice of him, Shigematsu's beast impales Mansam through the back. A stunned Mansam falls to the ground. However he remembers that he promised never to lose a fight unless it were against President Ichiryuu, and he gets back up. The fight is not seen but both men survive the ordeal, Shigematsu seemingly unscathed. Shigematsu is next seen with all of the NEO members back at their headquarters and with Joa leading, they head off to celebrate their victory over both the IGO and the Bishokukai.
None of Shigematsu's powers and abilities have been revealed yet, but it can be assumed that he has Gourmet Cells and given that he was the Vice President of the IGO directly under Ichiryuu (said to be the strongest man in the world) Shigematsu is likely one of the strongest people alive.