Psionic Lad made his first appearance in Superboy #3, written by Jeff Lemire; the series is ongoing.
Characters History of Sajan Mehra, Psionic Lad
Psionic Lad comes from a future version of Smallville called Akropolis in the year 2216. In this timeline, a warlord called The Hunter has rebuilt the city in his image, walling in the people and using them as slave labour to fuel his war efforts against the rest of the world. Akropolis is a dystopia, with the people having little hope.
Psionic Lad is a member of a group of underground dissident heroes. When the team is slaughtered during a "final battle" (one which Mehra survived due to his mental powers,) he travels back in time to seek mentoring for Superboy, one of the "greatest of his generation." Psionic Lad insists that Superboy teach him, as he seeks to become his own hero and help the people free themselves. He is persued by the Science-Hunters; a future version of the Science Police who can neutralize both Kryptonian and Mehra's powers.
He reads the mind of a catatonic Smallville citizen, Mr. Gilliam, who spoke of doom in the future times. Mehra sees the vision, but cannot comprehend it. Superboy then puts him up in a room at the Kent Farm.
Not all is what it seems, though; in private, Mehra enters communication with one of his thought-dead teammates and reports that he has infiltrated "the target's" inner circle. He also says that he will kill him at first opportunity.
Later when Simon is in Ivy town meeting with Ray Palmer, Sajan is seen lurking in the shadows. And later back in Smallville after a run in withe the Black Mercy, Sajan is talking to a thought-dead teammate again and tries to explian to her that maybe the Prime Hunter isn't really Simon. The transmision is intrupted by the Phantom Stranger.
Later in the lair of teh the Hollowmen, Sajan is contacted again, but this time he tell the woman "I woundn't kill him" but is knocked out by parasite. When he comes to he helps The Phantom Stranger return the souls of Smallville.