Rou

Race: Goblin (Day 1)

Hobgoblin (Day 13)
Ogre (Day 34)
Apostle Lord (Day 107)
Vajrayaksa Overlord (Day 245)
Affiliation: Goblin Community, Parabellum
Rank: Colonel/1st in the Goblin Community

Rou, whose former name was Tomokui Kanata, was a human with an esper ability. One day, he was killed by someone whom he regard as a sister and a stalker. Later, he woke to find out he was reincarnated as a goblin, a monster species considered to be of the lowest class. His memories as a human remained with him, however. Having a second chance at life, Rou was determined to live his life to the fullest.

(Source: Re:Monster Wikia, edited)