Start with "Eragon"... ends with "Inheritance".

Not long ago, Eragon - the current Shade Rider, Dragon Rider - was nothing more than a poor village boy, and his dragon, Saphira, a blue stone in a forest. Today, they carry the destiny of an entire civilization on their shoulders.
Endless months of training and battle have brought victories and hope, but also sad losses. The great battle has not yet taken place: they still have to face Galbatorix. When that moment comes, they must be strong enough to defeat him. And if they can't, no one else can. There will be no second chance. The Dragon Rider and his dragon have gone much further than anyone could imagine. But can they overthrow the corrupt king and bring justice back to Alagaesia? And if so, at what cost? And so, in a magical way, the "Inheritance" cycle by Christopher Paolini comes to an end, which has become a bestseller worldwide and is eagerly awaited by Greek avid readers.