Hand-reared dragon.

[/U]By the way, regarding the "mana accelerator." It's a bit expensive (in terms of Fury). And the more you develop it, the bigger the gap becomes. But it's really useful at the beginning :).

You're wrong! My dragon, level 53, now gives 19 mana and two action points for 16 Fury. The total amount of Fury is 85, so it's very cheap and useful.
PS Upgraded: 25 for 25 - just enough for a level 3 Phantom.