Its whereabouts are currently unknown. No Signer (past or present) has been shown to possess it yet, making it the only one of the original Signer Dragons to have not appeared as a Duel Monsters card to date.
"Power Tool Dragon", which belongs to Leo, looks like a mechanized version of Life Stream Dragon. Leo mistakenly believed "Power Tool Dragon" to be the (then) Fifth Dragon and believed himself to be the Fifth Signer after asking Luna if "Power Tool Dragon" took part in the ancient battle between the Signer Dragons and the Earthbound Immortals. Luna replied that maybe it did, but only just to make him happy; she didn't think it was the same Dragon, since such a high-tech robotic dragon couldn't have taken part in the ancient battle.
It also appears in in the Japanese Yu-Gi-Oh! 5D's opening theme "BELIEVE IN NEXUS" and the ending themes "CROSS GAME" and "Close to you".