Otto is a giant tardigrade that befriends Eva Nine in The Search for WondLa. He and Eva share a telepathic connection through the Vitae Virus.
History
Some time before meeting Eva Nine, Otto and his mate were separated from their herd and captured by Besteel. Otto's mate was killed for food, but Eva and Rovender Kitt managed to free him. In return, Otto helped them escape, and remained loyal to Eva Nine for saving his life.
The Search for WondLa
After Otto's first appearance in the book, he helped Eva and
Otto consoling Eva after Muthr's death.
Rovender escape from Besteel's camp and return to Sanctuary 573.