However, this Doctor was born in a separate body than the original Doctor, existing as a separate person with DNA sampled from Donna Noble. These genetic alterations caused him to develop a unique, less merciful personality that deviated from the moral code that his counterpart followed. The new Doctor needed someone to look after him and quell the fire in his veins, and shared the same romantic feelings toward his companion Rose Tyler that the original Doctor could not accept as a slow-aging Time Lord. Thus, the Tenth Doctor made sure this version of himself would enjoy his life with Rose Tyler in Pete's World, fulfilling the need to make him a better person, and so his duplicate could give Rose the romantic life that she desired in his stead.