Steve Dayton, one of the world's richest men in DC Comics, builds a helmet that enhances his own latent mental abilities and begins adventuring as the solo hero Mento for a short time but Rita Farr AKA Elasti-Girl of the Doom Patrol catches his eye and he goes out to impress her. He soon joins the Doom Patrol and in Doom Patrol #104, in July 1966, he and Elasti-Girl get married. Later, the newly weds adopt Gar Logan, the animal shape-shifter Beast Boy.

After the Doom Patrol dies, Mento goes mad and thanks to his addiction to the Mento helmet, develops a brain tumor that slowly deteriorates his sanity. He blamed his adoptive son, Beast Boy, then Changeling for the deaths of the Doom Patrol and even tried to kill Changeling and his fellow friends and teammates, the New Teen Titans in New Teen Titans #14. He then creates the "supervillain" group the Hybrid and tries to take the lives of Changeling and the New Teen Titans.

In the final battle against the Hybrid in New Teen Titans (vol. 2) #34, Raven uses her soul-self to enter the mind of Mento and cures him of his tumor. Father and son have tearful reunion. Steve Dayton also assists Deathstroke and Raven's mother, Arella, in finding the Teen Titans captured by the Wildebeest Society in New Titans #71, upgrading his helmet.

Not long after, Mento becomes the Crimelord and frames Deathstroke for murder but is revealed that Deathstroke is innocent and Crimelord is the true culprit. At the same time, Crimelord tried to plant nuclear bombs all over the country but he is defeated by a large group of superheroes, namely former and current members of the Teen Titans.

In the One Year Later event in DC, Steve Dayton is revealed to be back on the restored Doom Patrol in Teen Titans (vol. 3) #36 and is on a creative streak, furiously writing novels, naming the helmet responsible. He faintly remembers his days as Crimelord and when he was mad but calls them a glitch in the helmet. He has retained his age but is clean shaven again and his costume resembles his original when he first joined the Doom Patrol albeit more colorful.

Seeing the truth as the Chief has been manipulating the whole team and was trying to get Kid Devil into their ranks, Mento takes a stand and shakes off the addiction, removing the helmet which the Chief was using to make him think hazily, and takes the leadership of the Doom Patrol from him. Thinking clearly for the first time in a long time, Mento with the Doom Patrol backing him up, kicks the Chief off the team and threatens the Chief if he evers tries to interfere again. In the process, Mento gets the respect he deserves to be leader.

Other Media:

Mento and the original Doom Patrol (without Niles Caulder) appeared in the Teen Titans animated series.