Set in the distant future, construction workers pilot mecha. One of them is killed and his memories are implanted in his clone - a thirty year old man in a five year old superpowered construction tool body.
This series is the reboot to the original Weekly Shonen Jump series Juuki Ningen Jumbor. This manga takes place in an alternate universe from the original story, but features many of the same characters.
Baru Crow woke up in 3007, finding himself revived in his own clone body (memory transplanted) which has a physical age of 5 years old, and in addition to that, his body was partly mechanized. His robot arms are linked up to and directly controlled by his brain's signals. He was told that the country had gone and the princess and the king disappeared, and he discovered that his mechanized body is very powerful. He was also told he was 'last of the series'
The two oneshots under the title of "Jumbor" from Ultra Jump connect with the original Jyuki Ningen Jumbor storyline, not this story.