It's cold, and Fin can't fight it.
Even after he escapes the frost, only ice lives inside the firebird. The inferno he wants is gone. It was stolen from the middle realm by the man whose flame he craves the most: Zoran, the third god of fire. After the loss of his kingdom, the god took back his gift to the mortals: fire.
They're all prisoners to the cold, and Fin can't take it. He wants to feel the blistering heat and once again be engulfed in flames.
Only then will the aching pain in his chest stop. He'd do anything, anything at all to stop this polar flux.