Montgomery Sebastian was the Grand Sage of the Tombstone Isles. He was the father of Marshall Sebastian and the grandfather of Mabel Sebastian. He wielded the Akagen: Giant Mammoth.
Background
Montgomery Sebastian was born in the Lodos province of Azuria. He spent the first 30 years of his life in the country, enlisting in the military, getting married and having a son. His desire to fully understand his Gen eventually became his one focus and he left his family to join the Sage Islands. His research and determination lead to him being accepted as a sage in the Tombstone Isles and eventually becoming the Grand Sage.
Sejurno
Destinies
The Golden Pillar Arc
Montgomery secretly visited Azuria following the murder of his son, in order to pay his respects to the dead and also collect firsthand information on the nature of his son's murderers from Jay Raider. After Jay explained that their assailants used Black Gen, Montgomery noted that he had suspected the presence of alternate forms of Gen. He left by boat after this exchange however claimed that he would be investigating the death of his son through his own channels.