Tobots are the titular type of transforming robots featured in, well, Tobot. Though created with standard robotic parts, including AI, their major distinguishing feature is their Mind Cores, which act as their "heart".
The root of the Tobots began during a robotics competition, where brilliant young minds including Limo Kwon, Franklin Char, and Sora Wang. Once the competition was over, Limo suggested to Franklin that they combine their technology - Limo's transforming car, merged with Franklin's Toborobot, could work wonders.
Under the guidance of Dr. Noh, their future work was focused on Tobot Zero, but he was formed with an unstable Mind Core that wouldn't function as intended. Franklin continued to work on two other Mind Cores to no avail, until his work was interrupted by his wife and his two young children. So-young began singing a lullaby for the two kids, causing the inactive Mind Cores to activate, indicating a success, and the two Mind Cores were left to the care of the children.
Unfortunately, the earlier Tobot Zero proved a failure when he was unable to respond to Limo's plea to save everyone during a fire, which took the lives of his wife and Franklin's, and rendered Franklin paralyzed.
Presumably between this incident and the main series, Tobots X and Y were completed, while Limo created Tobot Z on his lonesome.
Though initially reluctant to create large numbers of Tobots, Franklin and Limo eventually began creating more at a faster pace due to the danger caused by Tom Fuse.
Combining Tobots are created by linking the smart keys of compatible Tobots together. If the combiners' systems are anything like Athlon Champion's, it can be assumed that a new personality is formed by the existing Mind Cores linking together.
Bold names indicate combiners that are currently active.