The Fusion
The fusion is when two souls recognise one another, this does not always mean they are or have to be lovers. However, the love of the two brothers that once was there but they've forgotten. This is why FengGe has taken to fusion so easily and LongWei not so much because he is resisting.
The fusion starts with the mind then their bodies come together: - The flames from the Phoenix encase the Dragon. It's like the Dragon is wearing a Phoenix outfit but the Phoenix controls everything.
In FengGe and LongWei's circumstances, FengGe controls the wings and its movements.He is also the keeper of the flame so he controls fire. LongWei however controls his ice power, that power fires through his claws instead of his tail.
"What is this, why can I not control anything?" LongWei asked frustratingly.
"LongWei stop your whining, you control your ice power" FengGe said to him. LongWei growled. "LongWei we are Gods now, it is what you always wanted. I know it is."
LongWei was speechless. He was shocked, though he should have known his brother knew all along. 'How did I not see this? Why was this detail kept from me?" LongWei muttered to himself.
"You should have stuck with me little brother. But I could not force you, so I had to let you decide your path on your own. Now we are ready," FengGe explained.