I remember reading a book/series of books about 10 years ago as a teenager, but can't for the life of me remember what it was called, and I'd love to read it again! Here are some details about the book/series in no particular order:
- There were three gems which were looked after (one was emerald-like)
- The guardians were a human, a snake and a falcon (I think called Rexel)
- One of the books starts with a couple flying across a vast empty space with the falcon, then they crash land in a forest
- The land they crash in has a kingdom which is being fought over by changelings (who are transformed by sitting in a pool of liquid for a few days) and knights who ride winged horses. The knights also have the aforementioned liquid-core swords which if I remember rightly are quite unwieldy when first used
the lead changeling used to be one of the princes, and when knights/people of the kingdom defect they normally elect to become a changeling and fight against the king
the gems can be absorbed for the user to gain extra powers (e.g. the falcon becomes supersized / the king become a gollum-esque creature in a cave that could rip changeling heads off)
there is a colony of humans on another world which lives in a large network of caves. In one of the books this colony was attached by a changeling army
That's about all I can remember off the top of my head, I can add more details if they come to me. I really hope that someone knows this series as it's been eating at me for a few years that I can't remember what the book was!
TIA for your help!