Turles is a Saiyan villain best known for his appearance in The Tree of Might, the third Dragon Ball Z movie. He's a former member of Frieza's army who went rogue and spent decades conquering planets on his own. He later showed up again in the Plan to Eradicate the Saiyans OVA.
At first glance, Turles is basically Goku's doppelgänger—same face, but with darker skin and a pair of horn-like protrusions in his hair. According to supplementary materials, low-class Saiyans all shared similar facial features, which is supposedly why they looked so alike. That said, Turles himself called Goku "low-class trash," which throws that explanation into question. He's actually got a pretty strong resemblance to Bardock, Goku's father, which fans have noted over the years.
Not much is known about Turles' exact age, though he appears roughly the same as Goku. Since he bailed on Frieza long before Kakarot was even born, he's probably older. The prevailing theory is that he survived Planet Vegeta's destruction by being off on a mission elsewhere. Roughly thirty years later, he and his crew head to Earth to check in on Goku.
His name is a vegetable pun—rearrange the syllables of ターレス (Tāresu) and you get レタース (retāsu), which is basically the Japanese spelling of "lettuce."
Content compiled by AnimeList.moe from publicly available sources.