A few things I forgot to clarify in the op:

1) Many people are animal people.  Humans exist but are just one of the mortal races.
2) Tech is limited to iron age and some steel, but many experienced dragon fighters/ dragon-kin use dragon parts in their equipment. 

Edit:

Bonding:
1) Bonding allows two beings to feel the relative strength and health of the other.  It also allows one being to slowly gain a trait the other has that they see as "superior" to their own traits and that they desire.  The other being, however, will not know what traits you are gaining unless you tell them, they see you using it, or they see a physical change in you.  The desire may also be subconscious, such as jealousy.
2) Changes occur faster the larger you perceive the disparity to be and the more you desire it, but are limited by the physical body.  Ex:  You may think that Dragon wings are the best advantage ever and crave them more than anything, but it will still take your entire a lifetime or more to get them if you are human, as they are contrary to your body's physiology.
3) Traits gained through bonding are hereditary, and have a 50/50 chance of being passed on to children, assuming only one of you has the trait.
4) Bonding requires a strong emotional connection between two beings.  The specific emotion doesn't matter, and can be different for each being in the bond, as long as it draws them towards each other.
5) At least one of the beings in the bond must have some degree of magical ability and control.  Without ability, the bond won't form, without control, the bond will grow unstable and break.

Known methods of forming a bond:
Assuming at least one of the two has magical ability and control, and both have a strong emotional pull towards each other:
1) One being saves the life of the other.
2) One being protects another from serious harm, though not necessarily mortal harm.
3) The two beings drink a drop of each others blood (Called the Vampiric bond, and is sometime stronger than other bond forms).
4) Two beings co-mingle their blood in their bodies (the usual method is to cut yourselves in a minor way and touch the wounds.
5) Sex (requires a very powerful emotional bond.  Only known to work with Lust, Love, and intense friendship which borders on love.)