Bloodsmelting makes your esper stronger, giving you better stats as it ranks up.
Quality from good to best:
Precious -> Heavenly -> Divined
It can take from 1 bloodsmelt to 100+ bloodsmelts before the quality goes up (and sometimes it may go down unfortunately...)
Getting a better quality (General Bloodsmelting):
Materials:
Main Esper (the esper you desire to be better)
Secondary Esper (the esper whose stats you are putting onto the Main one)
-For Lvl 75 and below espers, use Trigrams since they're cheap
-For the 105+, it's best advised to use at least the lvl 15 espers because Trigrams become so ineffective.
*You really want to have "Heavenly" or "Divine" quality but only doing this can be pretty costly for the 105 esper.
Esper Medium (can be acquired from trading in Treasure Bowls into Tonni in SS)
-Get the right one for your esper
Once you acquire the materials, go to any Esper Mystic, click Bloodsmelt, put in the materials into right slots and bloodsmelt away.
Ok, now to put that Orange Stat onto your Esper:
It's basically the same as regular bloodsmelting but special
Get a Secondary Esper with the orange stat you wish to transfer to your Main Esper.
Acquire a Best Dragon Skin (for lvl 75+ Espers, I think Blood Wine for 75-) b/c it's used as the medium for the transfer of the orange stat.
Now go to Esper Mystic and bloodsmelt like normal. The orange stat should be on the Main Esper now. It's best to bloodsmelt 3-4 Heavenly/Divined for everytime you bloodsmelt an Orange stat onto the Main Esper to keep from the other stats from lagging behind when you rank up.
P.S. AFAIK, you can only have one orange stat.
Feel free to pm in game or leave a comment here.
I would really like to get my hands on Dragon Crown.