Você está definitivamente falando sobre a série Broken Sky de Chris Wooding.
Muito difícil de encontrar, não tenho certeza se ainda está em impressão. Eu também li isso há 12 anos e lembro bem da luta do Golem.
The story revolves around the journeys and trials of twins Ryushi and Kia. Forced to flee from their home during a violent and seemingly unprovoked attack by the forces of the King they adored, they are pressed to reconsider their naive world-view caused by their sheltered upbringing as they are caught up in events beyond their control and larger than either of them imagined. What starts with an underground resistance soon develops into a full-fledged rebellion against the tyrannical King Macaan and his equally malicious daughter Aurin, with Kia, Ryushi and all those close to them at the center of it all.
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While the societies in Broken Sky rely on various infrastructures for their survival, such as water or Tusami City's magma-based geothermal power, one commodity which appears to rule many facets of daily life is the Spirit Stone. Extracted by mining as an inert, colourless gemstone, the Spirit Stones only take on their characteristic colour after being implanted by a Deliverer during a ritualistic ceremony called the pah'nu'kah.
During the ritual, the Spirit Stones are implanted along the spine - specifically, in the voids between their vertebrae - of a newborn child, being partially phased into their bodies so that only one hemisphere is visible. Once the ritual is complete, both the stones and the child forge a connection with the ley lines - conduits of raw energy running beneath the earth - giving the stones a specific colour and the child command over a certain ability later in life.
